Abstract: To solve the problems that the strength and plasticity of martensitic stainless steel are difficult to improve simultaneously, TiC nano-particles are introduced to refine the grains of stainless steel matrix.Martensitic stainless steel reinforced by TiC nano-particles with particles content of 0.25wt% was prepared by non-consumable vacuum electric arc furnace, and compared with as-cast stainless steel.The results show that the average size of retained austenite grains of TiC nano-particle reinforced steel decreases from 234.4 μm to 62.9 μm, and the main distribution range is from 50-350 μm to 20-100 μm.After heat treatment, TiC nano-particles reinforced steel is composed of refined laths and sub-micron cellular retained austenite between laths, the tensile strength of the reinforced steel is increased by 23.31%, the microhardness increases by 7.12%, and the elongation increases by 99%, which improve the strength, hardness and plasticity of matrix steel simultaneously.