Adopted the dual vacuum smelting process, the affection on the steel microstructure and mechanical properties of different CrE, NiE ratio was studied. The results showed that: the lower the CrE / NiE ratio was ,the Martensite organization of the steel after quenching and tempering was more complete ， the fewer the number of ferrite，while the comprehensive performance was more desirable. For a higher ratio of CrE / NiE , quenching and tempering system can be adjusted to compensate for performance deficiencies.