Abstract: In view of severe service conditions of heavy-load railway frog,a new self-developed bainitic steel for heavy-load railway frog was subjected to multi-frequency impact tests to observe and analyze its microstructure and hardness change pattern.The results show that,the grains of new bainitic steel for heavy-load railway frog after multi-frequency impact are fragmented and deformed,the grain boundaries become blurred,the content of residual austenite is reduced,the plastic deformation and work-hardening phenomenon occur on its impact surface. The microstructure of its impact surface is further fibrillated and the work-hardening effect is also more obvious.