We aimed to investigate the expression of Piwil2, Stat3 and Bcl-2 proteins and their location correlation in sterile male mice. Methods: 60 male Kunming mice were randomly divided into the experimental group and the control group, 30 in each group. The sterile mice were modeled with administration of Chinese herb Tripterygium wilfordii for 28d. The control group was intragastrically administered with the same dose of normal saline for the same duration. After modeling, two groups of male mice were mated with female mice respectively. The samples are respectively detected for expressions of Piwil2 protein, Stat3 protein and Bcl-2 protein by immunohistochemical staining and Western blot. We compared the expressions of these three proteins between the two groups. The HE staining showed that the structure of seminiferous tubules in the testis tissue of the experimental group was significantly damaged, the number of spermatogenetic cells including spermatogonia and primary spermatocytes was significantly reduced, and the fertilization ability was significantly decreased after mating, indicationg that the model establishment was successful. The results of IHC staining showed that the expressions of Piwil2 protein, Stat3 protein and Bcl-2 protein and the number of positive cells in the experimental group were significantly lower than those in the control group (P < 0.001) (Table 2). Western blot results also showed significantly decreased expressions of these three proteins in the experimental group than in the control group (Piwil2 protein: P < 0.05, Stat3 protein: P < 0.05, Bcl-2 protein: P < 0.01) (Fig. 3, Fig. 4). This study shows that the expressions of Piwil2, Stat3 and Bcl-2 proteins in the testis may play important roles in the occurrence of infertility.