This study investigates the effects of trastuzumab on the proliferation and apoptosis of ovarian cancer cells. Epithelial ovarian cancer tissues were collected from 60 patients, benign ovarian tissues from 45 patients and normal ovarian tissues from 30 patients. Human epidermal growth factor receptor 2 (HER2) protein expression was measured by immunohistochemistry and mRNA expression by quantitative real-time polymerase chain reaction (RT-PCR). Proliferation and apoptosis of SKOV3 cells were then measured by MTS assay and flow cytometry and cleaved caspase-3 expression was detected by Western blot. Our results established that HER2 protein is expressed in tumor tissues, benign tissues and normal tissues and its positive expression rate in tumor tissues is significantly higher than in benign tissues and normal tissues (p<0.05). In addition, the relative HER2 mRNA expression in epithelial ovarian tumor tissues was 55 times higher than that in normal ovarian tissues (p<0.01). Our research confirmed that trastuzumab significantly inhibited SKOV3 cell proliferation and increased cell apoptosis and cleaved caspase-3 expression in the experimental group compared to controls (p<0.05). In conclusion, HER2 protein is over-expressed in epithelial ovarian cancer tissues, and trastuzumab exerts anti-tumor effect by inhibiting cell proliferation and inducing apoptosis, suggesting it might be a novel approach for the treatment of ovarian cancer.