In order to improve the wear uniformity of inner surface and the mating with ring for cylinder liner, the cylinder liner samples were prepared under the two processes of plasma beam quenching/sulfurization. The microstructure and properties of inner surface were studied by OM, SEM, XRD and hardness tester. The results show that the quenched layer is composed of martensite and residual austenite and the quenched/sulfurized composite layer is composed of α-Fe+FeS+FeS₂. As the scanning speed gradually decreases, the hardness of quenched layer gradually increases and the hardness, thickness and FeS content of quenched/sulfurized composite layer gradually increase from bottom to top. Compared with the quenched cylinder liner sample, the wear of quenched/sulfurized cylinder liner sample is 0.003 mm and reduces by 66.7%, and the opening clearance of auxiliary ring reduces by 65.3%. The hardening effect for the inner surface of quenched cylinder liner gradually increases from bottom to top and its supporting effect on FeS gradually enhances, which is basically consistent with the requirements of wear resistance from the changes of actual working conditions in different parts of cylinder liner and the main mechanism of uniform wearability for the two cylinder liner specimens.