Abstract: Objective : To study expression of Cyclin G₁、Cyclin D、p21、p16、p53、bcl-2,apoptosis and change of cell cycle in mice-borne gastric carcinoma. Methods :Mice models with gastric carcinoma cell were establisted. The protein expression of Cyclin G₁, Cyclin D, p21, p16, p53, bcl-2 was measured using immunotistochemical method; The expression of Cyclin G₁ mRNA was measured with RT-PCR; Rate of apoptotic cells and cell cycle were detected by Flow cytometry. Results :Expression of Cyclin G₁ and Cyclin D in positive groups was significantly higher than in normal and chemotherapy groups (P<0.05), but that of p16 was reverse. Expression of p21 and bcl-2 showed no difference (P>0.05) in all groups; Expression of p53 in positive groups was negative, in other two groups it showed no difference (P<0.05). The expression of bcl-2 showed no difference (P>0.05); Rate of apoptotic cell in chemotherapy group and postive group was higher than that in normal group (P<0.05), and chemotherapy group was obviously higher than normal group(P<0.01). Conclusions :Gastric carcinoma relates to a higher expression of Cyclin G₁, Cyclin D and lower expression of p16.