This study investigated the prognostic impact of lymph node dissection (LND) in patients with stage I ovarian endometrioid carcinoma (OEC) and aimed to identify the optimal LND range for improved survival. By analyzing data from the Surveillance, Epidemiology, and End Results (SEER) database conducted in USA and NUWA database in China, we found that patients who underwent LND in the SEER cohort exhibited significantly improved long-term survival rates compared to those who did not undergo LND, while the difference was not statistically significant in the NUWA cohort. Cox regression and restricted cubic spline analyses indicated an inverted U-shaped association between the number of LNDs and hazard ratios, identifying 29-34 lymph nodes as the optimal range. This finding suggests that performing LND within this specified range may enhance survival outcomes for patients with stage I OEC.