【Abstract】 Objective To investigate the effect of the expression of the target silencing CDCA5 gene on the proliferation of human colorectal cancer cells and its possible mechanism. Methods Western blot was used to detect the expression of CDCA5 protein in colorectal cancer tissues, adjacent normal tissues and human colorectal cancer cell lines HT29, HCT116 and SW480 cells. siRNA for CDCA5 gene, negative control siRNANC and three different asymmetric small interference RNA, namely aiRNA (15/21), aiRNA (16/21) and aiRNA (17/21)were designed. The effect of CDCA5 gene silencing was detected by PCR. MTT assay was used to detect the proliferation of siRNA, siRNANC and aiRNA (15/21) cells. Flow cytometry was used to detect the changes of cell cycle in three groups. Results The expression of CDCA5 in colorectal cancer tissues was significantly higher than that of normal tissues adjacent to the cancer (P＜005). The expression of CDCA5 protein in human colorectal cancer cell line HCT116 was significantly higher than that of HT29 and SW480 cell lines (P＜005). AiRNA (15/21) had the strongest gene silencing effect in each group (P＜005). Compared with siRNA and siRNANC group, the proliferation ability of aiRNA (15/21) group was significantly lower than that of the other two groups, and the number of cells in the G2/M phase of cell cycle was significantly more than that of the other two groups (all P＜005). Conclusion CDCA5 may be an important target for the treatment of colorectal cancer. The specific asymmetric aiRNA (15/21) interference based on CDCA5 gene is superior to traditional siRNA in the efficiency of silence.