Objective To understand the new characteristics of clinical symptoms of patients with mild COVID-19 during the prevalence of SARS-CoV-2 Omicron, and provide basis for better prevention and treatment of COVID-19.Methods A cross-sectional retrospective study was conducted with WeChat questionnaire among medical staff with COVID-19 recently, who come from the Third Affiliated Hospital of Chongqing Medical University and The Second Affiliated Hospital of Army Medical University.Results A total of 630 valid questionnaires was received. 99.2% of infected people had been vaccinated against COVID-19. 2.4% of infected persons developed pneumonia and 2.1% were hospitalized. The most common symptoms after infection were coughing (89.7%), fever (83.0%), fatigue (84.1%), headache and dizziness (75.7%), muscle soreness (72.7%), sore throat (62.1%), nasal congestion and runny nose (60.6%), expectoration (71.6%), anorexia (58.0%) and taste loss (40.2%). The incidence of gastrointestinal symptoms and cardiovascular symptoms was relatively low (17.8% and 31.0% respectively). The severity of self-reported symptoms of most infected persons was moderate or severe. The proportion of serious symptoms reported was coughing (23.8%), sore throat (27.0%), headache and dizziness (17.9%). The severity of symptoms reported by young group (<35 years old) was significantly higher than that of older group (>35 years old). Fever was the highest at 38 to 39 ℃ (52.4%). 77.0% of fever sustained for 1 to 3 days. At the time of investigation, the viral detection turned negative in 60.6% of infected people, and the time of turning negative was mostly 7 to 10 days. More than half of the infected persons still had different symptoms, among which cough (43.7%) and fatigue (23.8%) were the most common.Conclusions Most subjects with mild COVID-19 infection have obvious upper respiratory tract and systemic symptoms, the most prominent is the high incidence of cough, which has become a new feature of omicron infection. And most of the infected people have moderate to severe symptoms, and the younger ones have more severer symptoms.