This study aimed to analyze the expression, clinical significance of cyclin G2 (CCNG2) in colorectal carcinoma, and the biological effect in its cell line by CCNG2 overexpression. Immunohistochemistry and Western blot were used to analyze CCNG2 protein expression in colorectal cancer and to study the influence of the upregulated expression of CCNG2 that might be found on SW480 cell biological effect. We found that the level of CCNG2 protein expression was significantly lower in colorectal cancer tissue than normal tissues (P < 0.05). The level of CCNG2 was correlated with T stages, lymph node metastasis, clinic stage, and histological grade (P < 0.05). Loss of CCNG2 expression correlated significantly with poor overall survival time by Kaplan-Meier analysis (P < 0.05). The result of biological function has shown that SW480 cell-transfected CCNG2 had a lower survival fraction, higher percentage of the G0/G1 phases, and lower CDK2 protein expression compared with SW480 cell-untransfected CCNG2 (P < 0.05).