CYP21A2, which is responsible for 21-hydroxylase activity, is prominent to the development of congenital adrenal hyperplasia (CAH). The aim of our current study is to investigate the role of CYP21A2 in the tumor processes. Here, we used HepG2 cell lines and generated CYP21A2 overexpressing vector and siRNA to investigate the effect of CYP21A2 on the tumor development processes, particularly cell migration and invasion; genes expression related to these processes were further examined. Results showed that CYP21A2 over-expressed or silenced had no effects on cell viability as well as the process of cell apoptosis. Further study suggested that CYP21A2 silenced significantly decreased the G0/G1 phase and increased the S phase of the cell cycle. However, no differences were observed when CYP21A2 was overexpressed. Moreover, we found that cell migration and invasion significantly improved with CYP21A2 overexpressed and impaired with silenced CYP21A2. Finally, we examined the expression of genes related to tumor processes and found that the Wnt signaling genes were changed. Taken together, our results demonstrated a novel function of CYP21A2 in the regulation of tumor processes, particularly cell migration and invasion, which this may be mediated by the Wnt signaling pathway.