Abstract: The composition design of 1000 MPa high strength steel was carried out by thermodynamic calculation, and three kinds of chemical components of 1000 MPa high strength steel welding wires were designed according to the results of composition design. By means of metallographic microscope, scanning electron microscope, microhardness tester and tensile test at room temperature, the effects of chemical components on the microstructure and mechanical properties of metal deposited by welding wire were studied, and the high-strength steel welding wire meeting the requirement of 1000 MPa was determined. The results show that the microstructure of deposited metal is mainly martensite. With the increase of the contents of Mo, Cr and Ni elements, the acicular ferrite content of deposited metal microstructure gradually decreases, and the martensite proportion and M-A island gradually increase. The mechanical properties of the deposited metals with three chemical compositions are different. Among them, when the main alloyed element mass fraction of the deposited metal is 1.58%Mn, 3.06%Ni and 0.70%Mo, the mechanical properties of the deposited metal are the best, the tensile strength and yield strength are 1114 MPa and 965 MPa respectively, and the elongation can reach 16%. The impact energy at -40 ℃ is as high as 62.0 J, which is consistent with the thermodynamic results