A Study to Compare QLS1128 With Placebo in Symptomatic Participants With Mild to Moderate COVID-19

Inclusion Criteria: 1. Male or female subjects between ages of 18-80 years. 2. Confirmed SARS-CoV-2 infection as determined by RT-PCR or antigen test in any specimen collected within 120 hours prior to randomization. 3. Initial onset of the COVID-19-related symptoms/signs within 48 hours prior to the randomization,and any of the following conditions are met on the day of randomization. 1. Score ≥2 for at least one symptom of body pain or muscle pain, headache,stuffy or runny nose,sore throat,cough,shortness of breath or difficulty breathing. 2. Risk factors associated with progression to severe/critical COVID-19 with a score ≥1 for at least one symptom of fever,muscle or body pain, headache,stuffy or runny nose,sore throat,cough,shortness of breath or difficulty breathing. 3. Score ≥1 for fever,with a score ≥1 for at least one symptom of muscle or body pain,headache,stuffy or runny nose,sore throat,cough,shortness of breath or difficulty breathing. Exclusion Criteria: 1. Previous treatment with QLS1128 sustained-release tablets or other 3CL protease inhibitors failed. 2. has received vaccines within 28 days prior to screening or planned to receive vaccines during the study period (including but not limited to COVID-19 vaccine). 3. Those who have a history of SARS-CoV-2 infection and still have symptoms related to COVID-19 during the screening period. 4. A history of SARS-CoV-2 infection, and the time of diagnosis of the latest infection to the time of diagnosis of the current infection is not more than 28 days. 5. Has received local approved anti-SARS-CoV-2 drugs within 7 days before screening or plan to receive them during the study period. 6. Has received monoclonal antibody against SARS-CoV-2 virus within 1 year prior to screening. 7. Has received convalescent plasma therapy for COVID-19 patients or expect to receive convalescent plasma therapy for COVID-19 patients during the trial. 8. Has received any CYP3A4/2C8 strong inducer within 14 days prior to screening or plan to receive any CYP3A4/2C8 strong inducer during the study period. 9. A known history of active liver disease , including acute/chronic hepatitis B, hepatitis C, cirrhosis, or acute liver failure. 10. Allergic or have contraindications to test drugs or test drug excipients.