Objective To compare and study the performance results of 300M steel after ceramic shot and cast steel shot peening and obtain the proper shot peening process of 300M steel. Methods 300M steel was shot peened by cast steel shot and ceramic shot at different intensities. The surface roughness, surface residual stress and fatigue life of 300M steel shot peened by two different shot methods were tested and researched. Results The surface roughness of 300M increased after shot peening by both ceramic shot and cast steel shot, but lower roughness value was achieved by ceramic shot peening under the same condition of shot peening intensity. The surface residual compressed stress first increased and then decreased with the increase of shot peening intensity by ceramic shot peening or cast steel shot peening. When the cast steel shot peening intensity was 0. 25A, the residual stress of the surface reached the maximum. For ceramic shot peening, the residual stress of the surface reached the maximum when the intensity was 0. 2A. Under the condition of large stress level test, the median fatigue life gain of the sample with different shot peening intensity of two kinds of shot was not obvious. However, under low stress level test conditions, median fatigue life gain was significantly different with different shot peening intensity of two kinds of shot, with the maximum value reaching 22 (steel shot peening) and 38 (ceramic shot peening), respectively. Conclusion The fatigue life could be increased by both cast steel shot peening and ceramic shot peening, but the 300M steel processed by ceramic shot peening had lower roughness level and longer fatigue life.