Coronavirus disease 2019 (COVID-19) has spread worldwide. To date, no specific drug for COVID-19 has been developed. Thus we performed this randomized, open-label, controlled clinical trial (ChiCTR2000029853) in China. A total of 20 mild and common COVID-19 patients were enrolled and randomly assigned to receive azvudine and symptomatic treatment (FNC group), or standard antiviral and symptomatic treatments (control group). The mean times of the first nucleic acid negative conversion (NANC) of 10 patients in the FNC group and 10 patients in the control group were 2.60 (SD 0.97; range 1-4) days and 5.60 (SD 3.06; range 2-13) days, respectively (p = 0.08). The mean times of the first NANC of 4 newly diagnosed subjects in the FNC group and 10 subjects in the control group were 2.50 (SD 1.00; range 2-4) days and 9.80 (SD 4.73; range 3-19) days, respectively (starting from the initial treatment) (p = 0.01). No adverse events occurred in the FNC group, while 3 adverse events occurred in the control group (p = 0.06). The preliminary results showed that FNC treatment in the mild and common COVID-19 may shorten the NANC time versus standard antiviral treatment. Therefore, clinical trials of FNC treating COVID-19 with larger sample size are warranted.