Determining the effects of adjuvant radiotherapy in patients with stage IB1-IIB cervical cancer that has invaded the uterine corpus. We retrospectively retrieved and assessed the data of stage IB1 to IIB cervical cancer patients with uterine corpus invasion (UCI) who had undergone radical hysterectomy from 2004 to 2016. The study endpoints were 5-year disease-free survival (DFS) and overall survival (OS). Additionally, independent factors associated with patients' survival were determined through multivariate regression models. A total of 284 patients from 11 institutions across China were eligible for this study. Among them, 90 (31.7%) had endometrial invasion, 105 (37.0%) had myometrial invasion < 50%, and 89 (31.3%) had myometrial invasion >= 50%. The 5-year DFS and OS of patients with myometrial invasion >= 50% within the uterine corpus who underwent adjuvant radiotherapy were significantly longer than those who did not undergo adjuvant radiotherapy. Furthermore, adjuvant radiotherapy was identified as an independent prognostic factor for improved 5-year DFS (adjusted hazard ratio (aHR), 0.484, 95% confidence interval (CI), 0.249-0.940) and 5year OS (aHR, 0.435, 95% CI, 0.204-0.925). However, we observed no significant survival benefit for patients with myometrial invasion < 50% or endometrial invasion within the uterine corpus following adjuvant radiotherapy. Adjuvant radiotherapy might lead to abetter prognosis in patients with stage IB1-IIB cervical cancer that has invaded the myometrium >= 50% within the uterine corpus but may not improve the survival of those with endometrial invasion or myometrial invasion < 50%.