At present, in view of measuring the radial problem of low precision for shaft parts, a non-contact laser three-point measurement method is proposed to establish mathematical model. Data acquisition system and data real-time system were designed, which could separate roundness error and rotational error, so as to improve the accuracy of measurement. The feasibility of the scheme is verified by case study, which provides a good technical reference for the study of radial circle run-out error of shaft parts.