We define trans-Sasakian Finsler manifoldF 2n+1 = (N ,N ,F) and semi-invariant submanifold F m = (N , N , F) of a trans-Sasakian Finsler manifoldF 2n+1 . Then we study mixed totally geodesic and totally umbilical semi-invariant submanifolds of trans Sasakian Finsler manifold.