Gastric carcinoma is one of the most prevalent malignancies with high morbidity and mortality. While chemotherapy is the major means for the management gastric carcinoma, tumors gradually exhibit drug resistance. Therefore, there is a need for agents capable of enhancing the sensitivity of tumor cells to chemotherapy. Herein, we have examined the effect of Celastrus orbiculatus extracts on chemosensitivity of drug resistant gastric carcinoma cells. Human gastric carcinoma cells (MGC-803 and SGC-7901) were cultured in the presence of cisplatin for the selection of drug resistant gastric cells. Next, the effect of C. orbiculatus extracts on multiplication capacity of drug resistant MGC-803 and SGC-7901 cells was examined by a variety of measures. Following C. orbiculatus extract treatment, the multiplication and invasiveness of drug resistant MGC-803 and SGC-7901 cells declined remarkably, with increased apoptosis and decreased levels of β-catenin, c-Myc, and cyclin D1 proteins, protein markers critical to cell proliferation, differentiation, and apoptosis. In summary, C. orbiculatus extract can effectively improve the sensitivity of cisplatin resistant gastric carcinoma cells to cisplatin and promote the apoptosis of tumor cells through the inhibition of the expression of proteins associated with the Wnt/β-catenin axis.