Objective To investigate how mutation of nuclear autoantigenic sperm protein (NASP) gene affects mouse liver fibrosis induced by concanavalinA (ConA) and its mechanism. Methods The wild-type B6 (B6-WT) mice were used as a control group, and the NASP mutant B6 (B6-NASPM) mice as an experimental group. The mice were injected with ConA via tail vein once a week for 8 weeks to establish the model of liver fibrosis. The histopathological changes were observed by HE staining, the collagen fiber deposition by Masson staining, smooth muscle alpha-actin (α-SMA) expression in liver tissue by immunohistochemical staining. The levels of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured by microplate assay. The serum tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) were measured by ELISA. The mRNA expressions of type I collagen (Col1) and Col3 in liver tissue were determined by real-time quantitative PCR, and the changes of T lymphocyte subsets in liver tissue were detected by flow cytometry. Results Compared with the B6-WT group, B6-NASPM group had disordered liver structure and no significant changes in mRNA expression of Col 1 and Col3, but the collagen fiber hyperplasia and α-SMA expression in liver tissue were more obvious, and the levels of serum ALT and TNF-α were significantly increased. In addition, the proportion and number of CD4+CD44hi T lymphocyte subsets in liver tissue were markedly decreased. Conclusion Mutation of NASP gene aggravates mouse liver fibrosis by increasing the release of TNF-α, changing the proportion of T lymphocyte subsets in liver tissue and promoting the activation of hepatic stellate cells.