Hepatocellular carcinoma (HCC) is closely associated with chronic liver disease and possesses a high incidence. DEP domain containing 1B (DEPDC1B) expression has been found to be upregulated in HCC according to bioinformatics analysis. This paper sought to study the specific role of DEPDC1B in HCC. The data of DEPDC1B expression and individual overall survival in HCC and normal liver tissues were acquired from UALCAN database. The association between DEPDC1B and the downstream signal, kinesin family member 23 (KIF23), was determined using LinkedOmics and STRING database, and subsequently confirmed by co-immunoprecipitation assay. The expression levels of DEPDC1B and KIF23 in normal hepatic epithelial cells and HCC cell lines were assessed by RT-qPCR and Western blotting, respectively. Following transfection with small interference RNA-DEPDC1B, the influences of DEPDC1B knockdown on cell proliferation, colony formation, cell cycle, cell invasion, migration, and KIF23 expression were evaluated. In addition, the effects of KIF23 overexpression on the above aspects of HCC cells were also determined, as well as the expression level of p53 signaling-related proteins. The results indicated that DEPDC1B was highly expressed in HCC cells. DEPDC1B knockdown inhibited the proliferation, migration, invasion, cycle, and KIF23 expression in HCC cells. Moreover, KIF23 overexpression reversed the inhibitory effect of DEPDC1B knockdown in HCC cells and the activation of the p53 signaling. In conclusion, DEPDC1B knockdown exerts anti-cancer role in HCC by activating the p53 signaling through KIF23.