70 CrMnMo martensitic steel welding materials are commonly used for surface and working face repair of tool steel. In this paper,in view of the large number of brittle fractures in 70 CrMnMo wire-drawing welding process,the material microstructure is analyzed by heat treatment principle,Ac1 phase transition point of the material was calculated and the accuracy of martensite tissue decomposition phase transition point was verified by experiments. Based on this,reasonable tempering process parameters were developed,and the ideal organization and performance were obtained quickly and efficiently by using self-made portable heat treatment equipment,which solved the problem of brittle fracture in the drawing production of 70 CrMnMo material.