【Abstract】Objective To compare the expression of ECadherin, βCatenin, PTEN, PI3K110α, pAktSer 473 and P53 proteins in low grade serous carcinoma (LGSC), high grade serous carcinoma (HGSC), early clear cell carcinoma (ECCC) and advanced clear cell carcinoma (ACCC), explore the dualistic mechanism of ovarian cancer (OC) and provide the basis for diagnosis and treatment of prognosis. Methods The ovarian serous carcinoma (OSC) was graded using a twolevel histological grade system at M.D.Anderson cancer center. The OC stage was staged using the international union of obstetrics and gynecology (FIGO) staging system. The expression of ECadherin, βCatenin, PTEN, PI3K110α, pAktSer473 and P53 protein in 22 LGSC,38 HGSC,20 ECCC, and 20 ACCC tissues was examined by immunohistochemical method and statistically analyzed in combination with clinicopathological features. Results The expression of ECadherin, βCatenin protein was statistically significant between LGSC and HGSC between ECCC and ACCC (P＜005). The expression of PTEN, PI3K110α, pAktSer 473 and P53 protein was statistically significant between LGSC and HGSC between ECCC and ACCC(Pp＜005). In LGSC, the expression of ECadherin and βCatenin protein was negatively correlated (P＜005). In HGSC, PTEN was negatively correlated with the expression of PI3K110α, pAktSer 473 and P53 protein (P＜005), and in ECCC, PTEN was negatively correlated with the expression of PI3K110α, pAktSer 473(P＜005). The difference between LGSC and HGSC between ECCC and ACCC between age≤50 and＞50 was statistically significant (P＜005). The difference between LGSC and HGSC between ECCC and ACCC between G1~2 and G3 was statistically significant (P＜005). The difference between clinical stage ⅠⅡ and ⅢⅣ was statistically significant between LGSC and HGSC between ECCC and ACCC (P＜005).Conclusion The deletion of ECadherin protein expression and the excessive activation of βCatenin protein may be involved in the occurrence and development of LGSC and ECCC. The deletion of PTEN protein expression and the excessive activation of PI3K110α, and pAktSer 473 protein may participate in the occurrence and development of HGSC and ECCC. The excessive activation of p53 protein is involved in the development of HGSC and ACCC, which provides a basis for exploring the dualistic pathogenesis, clinical diagnosis and treatment of OC.