To investigate the expression of mitogen activated protein kinase phosphatase-1 (MKP-1) and phosphorylation extracellular signal-regulated kinases (p-ERK(1/2)) in primary ovarian epithelial tumor tissues, and provide experiment's foundation on the new treatment in ovarian cancer. Expression of MKP-1 and p-ERK(1/2) in tissues from 64 patients with primary ovarian epithelial tumor, 35 patients with ovarian epithelial bordline tumor, 32 patients with ovarian epithelial benign tumor and 26 normal ovarian tissues was detected by immunohistochemistry. Western-blot was also used for detecting the expression of MKP-1 and p-ERK(1/2) protein in these tissues. Immunohistochemistry and Western-blot assay showed that the expression of MKP-1 was gradually decreased in normal ovarian tissues, benign tumor, bordline tumor and carcinoma respectively, and there were significant differences among them (P < 0.01). The MKP-1 expression level in the carcinoma tissues of stage III/IV patients was significantly lower than that of stage I/II patients. However, the expression of p-ERK(1/2) was gradually increased in normal ovarian tissues, benign tumor, bordline tumor and carcinoma respectively, and there were also significant differences among them (P < 0.01), the p-ERK(1/2) expression level in the carcinoma tissues of stage III/IV patients was significantly higher than that of stage I/II patients. Expression of MKP-1 and p-ERK(1/2) in same ovarian carcinoma tissues detected by immunohistochemistry and Western-blot assay showed significant negative correlation (r = -0.90, P < 0.01 and r = -0.78, P < 0.01 respectively). The expression changes of MKP-1 and ERKs may play a role in the development of ovarian carcinoma. The abnormal expression of MKP-1 and p-ERK(1/2) probably assists in promoting the development and progression of ovarian carcinoma.