This paper introduces a two-dimensional roller measurement mechanism according to the requirements of locomotive wheelset parameters measurement process. This mechanism makes it possible for single measurement head to measure the dimension parameters of a wheelset on axial and radial. It puts forward some methods on reducing parameters of wheelset systematic measurement errors after analyzing the structure of measurement mechanism. Automatic measurement system made by this two-dimensional roller measurement mechanism has high measurement efficiency and accuracy, strong anti-interference ability and operational reliability. The measurement system has been successfully applied in enterprise production.