Introduction: There has been no report regarding the impact on male sexual life or sexual function by changes in lifestyle during the coronavirus disease 2019 (COVID-19) epidemic. Aim: To investigate the changes in sexual life and sexual function of Chinese men during the COVID-19 epidemic. Methods: An online questionnaire was created and the survey was administered through social media to Chinese adult men. Main Outcome Measure: The main end point was the deteriorated erectile function or ejaculatory control ability, defined by self-evaluation or by decreased International Index of Erectile Function-5 items (IIEF-5) scores or increased premature ejaculation diagnostic tool (PEDT) scores. Results: Altogether, 612 questionnaires were collected. About 322 (52.6%) subjects were unmarried. About 8.4% and 8.5% subjects reported deteriorated erectile function or ejaculation control ability by self-evaluation, whereas 31.9% and 17.9% subjects showed decreased IIEF-5 scores or increased PEDT scores. Subjects with deteriorated erectile function by self-evaluation and decreased IIEF-5 scores had higher General Anxiety Dis-order-7 (P <.001 and P =.001) and higher Patient Health Questionnaire-9 score (P <.001 and P =.002) after the epidemic, decreased frequency of sexual life (P <.001 and P <.001) and physical exercise (P =.009 and .007) after the epidemic. Subjects with deteriorated ejaculation control ability by self-evaluation and increased PEDT scores had higher General Anxiety Disorder-7 (P <.001 and P <.001) and higher Patient Health Questionnaire-9 score (P <.001 and P =.002) after the epidemic. Subjects with decreased frequency of sexual life had reduced income (P <.001), increased anxiety (P <.001) and depression (P <.001). Married subjects had higher proportion of improved depression (P =.048) and increased frequency of sexual life (P =.010). Conclusion: During the COVID-19 epidemic, decreased sexual function was present in a certain proportion of adult men, and the risk factors include increased anxiety and depression, and decreased frequency of sexual life. Copyright (C) 2020, The Authors. Published by Elsevier Inc.