PurposeTo measure the sexual activity of breast cancer survivors and their partners to better understand the causes of sexual inactivity and sexual dissatisfaction in this population.MethodsWe investigated the proportion of sexual activity and sexual dissatisfaction in a cross‐sectional study and described their association with sexual health information sexual thoughts, socio‐demographic factors, body image, marital satisfaction, and mental health problems. We enrolled 438 eligible couples by convenient sampling. The statistical analysis and graphical work were completed using SPSS and Graphpad Prism.ResultsOf all participants, 58.66% (257/438) reported being sexually inactive. Of the 41.3% (181/438) sexually active participants, 96.7% (175/181) were considered to have sexual dysfunction. Patients’ sexual knowledge related to their disease, such as “sexual activity may impede disease recovery (AOR = 1.642; 95% CI: 1.119~2.409)”, “sexual activity may cause cancer recurrence or metastasis (AOR = 1.526; 95% CI: 1.012~2.302)”, “sexual activity could change the estrogen level and stimulate tumor growth (AOR = 1.585; 95% CI: 1.021~2.460)” were significantly associated with sexual inactivity. Psychological issues related to sexual activity, and hospital's sexual health resources, such as“anxiety (AOR = 2.141; 95% CI: 1.400~3.272)”, “depression (AOR =2.082; 95% CI: 1.317~3.293)”, “feeling less feminine as a result of your disease or treatment (AOR = 1.526; 95% CI: 1.012~2.302) ”, “dissatisfied with their physical appearance (AOR = 1.514; 95% CI: 1.010~2.271) ”, “medical providers provide information on sexual health (AOR = 4.459; 95% CI: 2.044~9.730) ”, “used sexual health aids (AOR = 1.514; 95% CI: 1.010~2.271) ” were significantly associated with sexual dissatisfaction. We also identified that the sexual demands of the partner led to increased sexual dissatisfaction among the survivors. ConclusionsMost Chinese breast cancer survivors were sexually inactive. Patients’ sexual knowledge related to their disease was the great barrier to sexual activity. Improving psychological problems associated with sexual activity and providing professional sexual health resources in hospitals can effectively improve sexual satisfaction among survivors. In addition, the impact of the partner's proactive needs on sexual satisfaction also needs to be considered when developing couples' therapy together.