Abstract: The 0. 20% ~0. 25%C high-quality NM450 wear-resistant steel for truck compartment has been designed and developed by using Nb, Ti, Cr and B microalloying composition. The microstructure of 14 mm steel plate queched at 900 °C and tempered at 200 °C is tempered lath martensite and a small amount of dispersed second phase particles, which has the excellent comprehensive properties. The tensile strength of NM450 steel is 1 459 MPa, the elongation is 19% , the impact energy is 104 J, the surface brinell hardness value is 450HBW. With the bending angle 180°and the elbow diameter 168 mm, the bending sample is qualified. CHW-70C welding wire has good welding performance： i. e. the tensile strength of welded joint 839 MPa, the impact energy of weld 113 J, the hardness number of weld 282HV. With the bending angle 90° and the elbow diameter 168 mm, the bending sample is qualified.