Abstract: To address the issue that railway frogs suffer impact from wheels under high-speed operation during service, compression tests were carried out on a self-developed new bainitic steel for heavy-haul railway frogs, and the evolution laws of its microstructure and hardness were observed and analyzed. The results show that with the increase of compression degree of the bainitic frog steel, the grain fragmentation is intensified, the microstructure becomes denser, and the grain boundary contours gradually become blurred. During plastic deformation of the steel, the retained austenite inside undergoes a phase transformation to martensite. As the deformation continues to increase, more fine subgrains are formed inside the material, and the number of subgrain boundaries increases accordingly. These microstructural changes significantly enhance the resistance to dislocation movement, leading to continuous accumulation of dislocation density, which in turn makes the work-hardening effect of the material increasingly prominent.