【Abstract】 Objective To investigate the impact of CDCA5 on the prognosis for patients with hepatocellular carcinoma (HCC) and explore its growthpromoting effect in hepatoma cells.Methods The clinical and pathological data of 178 patients underwent curative hepatectomy of HCC were analyzed, retrospectively. The expression of CDCA5 in tumor, and normal liver tissues was detected by immunohistochemistry. The impact of CDCA5 on clinicopathology and prognosis was analyzed. Plasmids were constructed to knock down and overexpress of CDCA5. The effect of different expression of CDCA5 on the proliferation of hepG2 cells was analyzed by MTT assay. The changes of cell cycle of hepG2 cells were detected by flow cytometry. Nude mice were injected with CDCA5 low expression and normal expression of HepG2 cells subcutaneously. Mice were sacrificed on the 30th day for the observation of tumor status. Immunohistochemistry was used to detect CDCA5 expression in tumor tissue of nude mice.Results The expression of CDCA5 in HCC was significantly higher than that in normal liver tissues. Patients with high expression of CDCA5 had larger tumor diameter, high incidence of microvascular invasion, poorer diseasefree survival and overall survival than patients with low expression of CDCA5. The results of in vitro experiments suggest that CDCA5 promoted the proliferation of liver cancer cells. HepG2 cells growth were arrested in G2 phase after knocking down CDCA5. The tumor weights were 089±007 and 066±011 in control group and CDCA5 knock down group, respectively (P＜005).Conclusion CDCA5 can significantly promote the proliferation of hepatocellular carcinoma. CDCA5 may become the target of hepatocellular carcinoma.