Abstract: The effects of chemical compositions, deformation temperatures and cooling rates on mechanical properties and microstructures of axle steel for railroad vehicle was investigated through comparison tests and thermo-mechanical simulation tests.Then, based on the front experiment, a new steel with 0.40% C-0.08% V-0.019% Ti was developed successfully.The new steel displays excellent tensile properties and invisible sensitivity to two different deformation temperatures applied.However, the cooling rates have great influence on microstructures of steel, which implies proper heat treatment is necessary for eliminating mixed grains inevitably occurred in practical product of steel axle.