Safety, Tolerance, Efficacy and Pharmacokinetics of JS005 Multiple Dosing

Inclusion criteria: 1. Male and female patients aged 18 \~ 75 years (inclusive, age limited to 18 \~ 60 years in Part I of the study); 2. Body mass index (BMI) = weight (kg)/ height 2 (m2), ranging from 18\~30 kg/m2 (inclusive) at screening; 3. Being able to understand the content of the study and voluntary to sign the informed consent form; meanwhile, being able to complete the study as required in the protocol; 4. Having been diagnosed as chronic plaque psoriasis for at least 6 months prior to screening; 5. Being eligible for systemic therapy. Defined as moderate to severe chronic plaque psoriasis poorly controlled with local therapy and/or phototherapy and/or previous systemic therapy; 6. At screening, moderate to severe plaque psoriasis will be defined as followings: PASI score ≥ 12, PGA score ≥ 3 (in accordance with 0 \~ 5-point scale), and body surface area (BSA) affected by plaque psoriasis ≥10%; 7. No plan of pregnancy and being willing to use effective contraceptive measures for patients (including partners) from signature of informed consent to 6 months after administration of investigational product, see Appendix 7 for the specific contraceptive measures. Exclusion criteria: 1. Prior biologic therapy (Secukinumab or Ixekizumab) that directly targets il-17 monoclonal antibody or IL-17 receptor at any time; 2. Use of a therapeutic biologic within 12 weeks prior to screening, or random administration of the drug during the elimination phase (5 half-lives), whichever is longer; 3. Participated in any other clinical study with investigational drug intervention within 12 weeks prior to screening, or the investigational drug was in the elimination phase (5 half-lives) at the time of randomization, whichever is longer; 4. Have received live vaccine within 12 weeks prior to screening, or plan to receive live vaccine within 12 weeks after administration of the last experimental drug; 5. Any infection requiring hospitalization, antiviral or antibiotic treatment within 30 days prior to screening (such as pneumonia, cellulitis, bone and joint infection, etc., and the investigator determined that the patient had low immune function and participation in this study might lead to unacceptable risks); 6. Received systemic treatment of Chinese herbal medicine for psoriasis within 30 days or external medication for psoriasis within 14 days prior to screening; 7. Have received systemic treatment for psoriasis within 30 days prior to screening or were using a prohibited treatment at the time of screening.As UV exposure is one of the contraindication treatments, patients who do not wish to limit their UV exposure (e.g., sunbathing and/or using tanning devices) during the study period will be excluded; 8. Non-chronic plaque psoriasis (e.g. Pustular psoriasis, erythrodermic psoriasis and intravenous psoriasis) at the time of screening; 9. Drug psoriasis (new or aggravated psoriasis caused by beta blockers, calcium channel inhibitors or lithium) at the time of screening; 10. The presence of other skin problems (e.g. skin infection, seborrheic dermatitis, severe allergic skin disease, etc.) that may interfere with the evaluation of psoriasis; 11. A history of inflammatory bowel disease, Crohn's disease, or other persistent active autoimmune disease; 12. Have a history of Tubercle bacillus (TB) infection, or chest imaging examination suggested TB infection during screening, or tuberculosis screening suggested latent tuberculosis infection; 13. History of transplantation of vital organs (such as heart, lung, liver, kidney, etc.); 14. A history or symptoms of malignancy in any organ system at the time of screening, whether or not it has been treated within the past 5 years, and whether or not there are signs of local recurrence or metastasis; 15. Having other significant medical problems at the time of screening, including, but not limited to, uncontrolled hypertension (systolic blood pressure ≥160mmHg and/or diastolic blood pressure ≥95mmHg), congestive heart failure (New York heart association status class III or IV); 16. Medical history and past history suggest other major diseases, including but not limited to gastrointestinal, renal, liver, neurological, hematological, endocrine, pulmonary, immune, psychiatric or cardiovascular and cerebrovascular diseases. The researcher considers that participation in this study would pose unacceptable risks to patients or significantly affect the study results; 17. Has undergone any major surgery within 8 weeks prior to screening, or is required to undergo such surgery during the study period, which the investigator and sponsor have confirmed may pose unacceptable risks to the patients; 18. Patients with serum creatinine above the upper limit of normal at screening time.Platelet \& LT during screening;100 x109/L, neutrophils \<1.5x109 /L, or hemoglobin \<85g/L, ALT or AST level increased ≥ 2 times the upper limit of normal value; 19. Abnormal electrocardiogram during screening was considered clinically significant by the investigator, and participation in the study may bring unacceptable risks to the patients; 20. At the time of screening, HBV DNA copy number was detected in persons who were positive for human immunodeficiency virus antibody (ANTI-HIV), hepatitis C virus antibody (anti-HCV), hepatitis B surface antigen (HBsAg) or HBcAb (upper limit of reference value of each hospital for quantitative test line); 21. Known to suffer from moderate to severe allergic diseases or hypersensitivity reactions; 22. Known history of allergy or hypersensitivity to study drugs, other monoclonal antibodies and therapeutic protein preparations (human serum albumin, cytokines, interleukins, etc.); 23. Screening and randomization of female patients with β -human Chorionic Gonadotropin (β-HCG) positivity or breastfeeding; 24. Blood loss or blood donation within the last 3 months \& GT;400mL, or patients who had received blood transfusion, or who planned to donate blood during the study; 25. Any other conditions considered unsuitable for study participation by the investigator, such as patients with other potential compliance problems, inability to complete all examinations and evaluations as required by the protocol, or uncontrolled neuropsychiatric or psychological disorders, present uncontrollable risks of study participation.