For achieving high precision measurement of linear profile for micro-parts,an evaluation algorithm of linear profile based on discrete points is proposed according to the imaging characteristics.Firstly,an edge detector is used to obtain the edge of the micro-parts.Then,a series of points with tiny interval can be calculated by the expressions of designed profile and a system coordinate is build for corresponding the points of actual profile and the points of designed profile.Finally,the minimum distance between every point of actual profile and the point of designed profile is taken as the linear profile error of the point.The experimental results show that the error is less than 2 pixel,so the proposed algorithm can significantly improve the precision and efficiency in the measurement of linear profile.