Abstract: Objective The article aims to investigate the expression and correlation of ALDH1 and CA125 in serum of epithelial ovarian cancer patients. Methods Select epithelial ovarian cancer patients 30 cases, ovarian benign tumor patients 30 cases, which was diagnosed by pathology in our hospital, and normal ovarian 30 cases as control group. Enzyme-linked immunosorbent assay(ELISA)method was employed to detect the levels of ALDH1 and ca125in patients’ serum. Result The level of ALDH1 in serum of patients with epithelial ovarian cancer was significantly higher than patients with ovarian benign tumor and normal ovarian(P<0.05).The difference between the groups was statistically significant(P<0.05).The level of CA125 in serum of epithelial ovarian cancer patients was significantly higher than ovarian benign tumor patients and there was no significant difference between patients with ovarian benign tumor and normal ovarian and stage Ⅰ+Ⅱ epithelial ovarian cancer patients.ALDH1 and CA125 in serum are positively correlation in epithelial ovarian cancer patients(r=0.434，P=0.016). Conclusion Indicate examination of ALDH1 in serum may be one of the means of screening epithelial ovarian cancer patients. The level of ALDH1 in serum of epithelial ovarian cancer patients were related to pathological staging of FIGO operation. The level of ALDH1 in serum of epithelial ovarian cancer patients may as marker reflecting the biological behavior of epithelial ovarian cancer. The level of ALDH1 and CA125 in serum of epithelial ovarian cancer patients have positive correlation,ALDH1 may have synergistic effects with CA125.