Efficacy and Safety Study of Calcipotriol Betamethasone Plus Calcipotriol in Sequential Therapy to Psoriasis

Inclusion Criteria: 1. Subjects who signed Informed Consent Form； 2. Male or female subjects 18-65 years of age； 3. Clinically confirmed diagnosis of plaque psoriasis as per the diagnostic criteria for psoriasis vulgaris specified in Clinical Dermatology. 4. Involved area 1-10% of the body surface area. Exclusion Criteria: 1. Incompliance with the diagnosis of plaque psoriasis or plaque area \> 10% of the body surface area. 2. Erythrodermic psoriasis, psoriasis arfhropathica or pustular psoriasis; 3. Known allergy to any component of the test or control drug； 4. Concomitant allergic skin disease such as eczema， contact dermatitis and urticaria, or other serious and/or extensive skin disease； 5. Systemic medication or ultraviolet therapy for psoriasis within 4 weeks prior to study initiation； 6. Topical use of external drug for psoriasis within 2 weeks prior to study initiation； 7. Women of child-bearing potential who are pregnant, plan to become pregnant during study or are lactating； 8. Glucocorticoid or immunodepressant, or hypoleukemia due to tumor or chemotherapy within the last 4 weeks； 9. Serious life-threatening condition that allows a life expectancy of less than 2 months； 10. Inability to guarantee taking medications and completing visits as scheduled during the study; 11. Serious infection that is not suitable for external treatment； 12. Any other condition that the investigator deems unsuitable for entering the study.