Objective To analyze the influence factors on nucleic acid negative conversion time in severe acute respiratory syndromes coronavirus 2(SARS-CoV-2) Omicron infected patients over 60 years old. Methods The patients over 60 years old infected SARS-CoV-2 Omicron in one designated hospital of Shanghai during April and June of 2022 were enrolled and the information including clinical data and nucleic acid negative conversion time were collected. The patients were divided into ≤14-day group and >14-day group based on nucleic acid negative conversion time, and clinical characteristics of two groups were compared. The correlation between age, time from diagnosis to Paxlovid use and nucleic acid negative conversion time was analyzed. Logistic regression analysis was used to analyze the influence of sex, age, vaccination, basic diseases and time from diagnosis to Paxlovid use on nucleic acid negative conversion time. Results The average day of nucleic acid negative conversion time was 15(12-18) d. As age and time from diagnosis to Paxlovid use increased, nucleic acid negative conversion time increased gradually (P=0.006, P<0.001). The univariate Logistic regression analysis showed that age, malignancy and time from diagnosis to Paxlovid use were related to nucleic acid negative conversion time ≤14 d (P=0.028, P=0.038, P=0.042). The multivariate Logistic regression analysis showed that age and time from diagnosis to Paxlovid use ≤3 d were independently related to nucleic acid negative conversion time ≤14 d (P=0.007, OR=0.802; P=0.003, OR=2.402). Conclusions In SARS-CoV-2 Omicron infected patients over 60 years old, increased age is related to longer nucleic acid negative conversion time, and the patients having malignant tumor also have delayed negative conversion time, while early using Paxlovid (≤3 d) could shorten nucleic acid negative conversion time.