Abstract: Objective To study the relationship between the expression of excision repair cross complementation group 1 (ERCC1)in circulating tumor cell (CTC) in peripheral blood of patients with epithelial ovarian cancer (EOC) and the sensitivity to platinum. Methods A total of 60 EOC patients in Chinese PLA General Hospital from March 2015 to June 2016 were enrolled. Peripheral blood of patients was collected before postoperative chemotherapy and within a week after the three courses of chemotherapy(carboplatin/paclitaxel). The Nanofiltration membrane and RNA in situ hybridization technique was used to separate and detect the CTC and ERCC1-positive CTC. The relationship between ERCC1-positive CTC and the sensitivity to platinum was analyzed. Results Of the 60 cases, CTC was observed in 50 cases (83.3%) and ERCC1-positive CTC in 36 cases (60%). According to the quantitative change of ERCC1 + CTC before and after chemotherapy, the 36 patients were divided into elevated ERCC1 + CTC group (ERCC1 + CTC-H group, 12 cases) and non-elevated ERCC1 + CTC group (ERCC1 + CTC-L group, 24 cases). No significant difference was between the two groups in age, family history, histology, ascites, ascites cytology, residual tumor, FIGO stage (P> 0.05). There were 15 cases (62.5%) in ERCC1 + CTC-L group and 2 cases (16.7%) in ERCC1 + CTC-H group were sensitive to platinum, with statistically significant difference between the two groups (P< 0.05). Conclusion The ERCC1 expression of CTC can predict the sensitivity to platinum.