The BALB/c-hTL1A (TNFSF15) mouse is a humanized model constructed by replacing the mouse Tnfsf15 gene in situ with the human TNFSF15 gene using gene editing technology, in which the mouse Tnfsf15 endogenous extracellular domain (aa.79~271) will be replaced with the human TNFSF15 extracellular domain (aa.57~252). The homozygous BALB/c-hTL1A (TNFSF15) mice are viable and fertile and can be used for studies on T cell differentiation and survival, immune response regulation, and pathogenesis of autoimmune diseases, as well as for TL1A-targeted drug development.