ObjectiveNumerous studies have shown that pelvic floor muscle training (PFMT) adherence in women with postpartum stress urinary incontinence is low and influenced by many factors. However, most previous studies have been cross-sectional studies on PFMT adherence. Neglecting physiological and psychological recovery after childbirth may lead to changes in the adherence to PFMT. This longitudinal study investigated the developmental trajectory of PFMT adherence at 8, 10, and 12 weeks postpartum and the associated factors in China. MethodsA total of 213 women with postnatal stress urinary incontinence who visited the obstetric pelvic floor clinic of a Grade A tertiary specialist maternity hospital in Beijing, China between January 2018 and January 2019 were selected. Compliance levels were measured using PFMT compliance questionnaires at 8, 10, and 12 weeks postpartum. Data on self-efficacy, postpartum social support, and other influencing factors were collected at 12 weeks postpartum. Differences in PFMT compliance scores were analyzed using repeated-measures analysis of variance. Multiple stepwise linear regression analyses were used for multivariate analysis. ResultsThe PFMT compliance scores at 8, 10, and 12 weeks postpartum were 13.47 ± 4.42, 10.76 ± 4.46, and 7.95 ± 5.54, which were at a moderate level and showed a decreasing trend over time. Multiple stepwise line regression analysis showed that the factors influencing compliance with PFMT in women with postpartum stress urinary incontinence were knowledge-attitude-practice of PFMT (t = 4.251, P < 0.001), postpartum social support level (t = 4.304, P < 0.001), and self-efficacy level of PFMT (t = 8.577, P < 0.001). ConclusionThe PFMT compliance of Chinese women with postpartum stress urinary incontinence was moderate, with a downward trend. More effective methods should be chosen to improve women's PFMT compliance based on their situation, such as improving patient self-efficacy, social support, and knowledge-attitude-practice.