To ensure the reliability of some industry producing equipments,the rapid calibration and measurement for diameter and installed eccentricity of rotating pieces with different sizes are required.In this paper,features of laser online calibration system were studied and relevant measuring signal formula were presented,and general principles to design such a system were given.Theoretical analysis shows that accuracy of such system could be up to micron level,which was identical with practice in precise PCB drilling machine.Analysis methods presented in this paper can be applied to lathe,milling machine,processing platform and so on,which need designing a rapid online measurement system and calibrating rotating piece for diameter as well as installed eccentricity.