Abstract: The roller is one of the key components in the composite cable saddle of suspension bridge, which has high requirements for mechanical properties.According to the requirements of composite cable saddle of lvzhijiang bridge, 12Cr13 stainless steel and 30Cr13 stainless steel were selected as the experimental objects.Through a series of experiments, the phase composition, microstructure and mechanical properties of the two steels were systematically compared, so as to provide data support for the material selection of composite cable saddle roller of suspension bridge. The results show that the microstructure of 12Cr13 is tempered martensite, retained austenite and a small amount of ferrite after quenching (oil quenching)+low temperature reheating heat treatment.The existence of ferrite ensures the toughness and plasticity of 12Cr13, makes it have good comprehensive mechanical properties, and fully meets the material selection requirements of composite cable saddle roller of lvzhijiang suspension bridge. The microstructure of 30Cr13 is tempered martensite and retained austenite.Compared with 12Cr13, its microstructure uniformity is improved and 30Cr13 has higher strength, but its plastic and toughness can not meet the design requirements.