To investigate the impact of preoperative hysteroscopy on progression-free survival (PFS) and disease-specific survival (DFS), and to explore the factors which contribute to poor clinical outcomes between hysteroscopy and dilation and curettage (D&C) in endometrial cancer (EC). A retrospective study was designed by collecting data from women diagnosed with EC through hysteroscopy or D&C from January 2010 to December 2019 in a tertiary hospital in China. A propensity score was used for 1:1 matching of advanced stage patients. Univariate and multivariate analysis were conducted to determine whether hysteroscopy was a prognostic factor in EC and to identify factors associated with its impact on PFS and DFS in different subgroups. Overall, 543 and 272 women who underwent D&C and hysteroscopy, respectively were included. Compared to D&C, preoperative hysteroscopy was related to reduced PFS and DFS, with a hazard ratio (HR) of 1.904 and 3.905, respectively. Hysteroscopy contributed to an increased risk of positive wash cytology (48.27% vs 24.13%), recurrence (48.28% vs 20.69%) and shorter PFS after matching in FIGO Stage I-IV EC, while there was no significance in positive ascites cytology (14.04% vs 13.45%), PFS and DFS in FIGO Stage I EC. Hysteroscopy was an independent predictive factor for poor prognosis in EC. Hysteroscopy appeared to be a safe diagnostic method as D&C in FIGO Stage I EC but was a risk factor for increased recurrence and reduced PFS in advanced stage disease. Its impact on DFS is uncertain.