A total of 60 mice were divided into model group， low dose of curcumin group， middle dose of curcumin group and high dose of curcumin group， with 15 mice in each group. The mice were inoculated with colorectal cancer LOVO cells to establish the mouse colorectal cancer models.The rats in low，middle and high doses of curcumin groups were given 25， 50 and 100 mg·kg^－1 curcumin by gavage， respectively， for 4 weeks.Twenty four hours after the last administration，the tumor volumes， tumor weights and the inhibitory rates of tumor of the mice in various groups were detected. Immunohistochemical staining was used to detect the expressions of proliferating cell nuclear antigen （PCNA） in tumor tissue of the mice in various groups，and the proliferation index（PI） of cells was calculated. HE staining was used to observe the pathomorphology of tumor tissue of the mice in various groups， and Western blotting method was used to determine the expression levels of proto-oncogene c-Myc， caspase3， PTEN， Akt and phosphorylated Akt （p-Akt） proteins in tumor tissue of the mice in various groups.

The tumor volumes， tumor weights， the inhibitory rates of tumor， PI values，and the expression levels of c-Myc， caspase3， PTEN and p-Akt proteins in tumor tissue of the mice in various groups had statistically significant differences （P<0.05）.Compared with model group， the tumor volumes and tumor weights of the mice in different doses of curcumin groups were significantly decreased（P<0.05），the inhibitory rates of tumor were increased（P<0.05）， the PI values were decreased（P<0.05），the expression levels of c-Myc and p-Akt proteins were decreased（P<0.05），and the expression levels of caspase3 and PTEN proteins were increased（P<0.05）. The immunohistochemical results showed that the number of PCNA positive cells in tumor tissue of the mice in different doses of curcumin groups were significantly less than that in model group.The HE staining results showed that the tumor tissue cells in model group were disordered， the nucleus-cytoplasm ratio was increased， and the nuclear staining was deep； compared with model group， the tumor tissue cells of the mice in different doses of curcumin groups were relatively neatly arranged， the nucleus-cytoplasm ratios were decreased， and the nuclear staining was light.The effects of curcumin on tumor volume， tumor weight，inhibiory rate of tumor， PI value of tumor tissue and the expressions of c-Myc，caspase3，PTEN and p-Akt proteins in tumor tissue were dose-dependent， and there were statistically significant differences in the indicators among different doses of curcumin groups （P<0.05）.

Curcumin can inhibit the tumor growth in the colorectal cancer mice，and its mechanism may be related to that curcumin can inhibit PTEN/PI3K/Akt signaling pathway.