In recent years, OCT-4 and AP-2γ have been widely used as clinical markers of testicular germ cell tumors. Transcription factor OCT-4, which plays an important role in embryonic development, gives full play to a variety of biological functions in different developmental periods and differentiations. The effect of OCT-4 is realized through the regulation of the target genes. In this study, we found OCT-4 binding sites within the sequence of AP-2γ promoter region by a variety of bionemerics. AP-2γ, a novel target gene of OCT-4, was identified by chromatin immunoprecipitation (ChIP) -PCR. A combination of sequence analysis, reporter gene assays, Western blot, immunofluorescence assay and mouse cryptorchidism model experiment further confirmed that AP-2γ was the target gene of OCT-4. OCT-4 inhibited the transcriptive activity of AP-2γ. The expression of AP-2γ gene was confirmed to be significantly altered by silencing or overexpression of OCT-4. This new discovery is conductive to study the malignant process of germ cell tumors at the molecular level.