Abstract: The impact tests of V-notch and U-notch were carried out on 34CrNi1Mo steel, and the curves of shear section ratio and test temperature were drawn. The influence of notch type on the ductile-brittle transition temperature of 34CrNi1Mo steel was analyzed by comparing the curves and the ductile-brittle transition temperature. The results show that the different notch types had a great influence on the ductile-brittle transition temperature of 34CrNi1Mo steel, and the ductile-brittle transition temperature measured by U-notch specimens were lower than that of V-notch specimens.