Abstract: To achieve the high precision measurement of the complicated deep-hole profile geometric parameters, the detection system for the profile based on the structured light was established. However the images collected by the camera had larger geometric distortion compared with the plane images from the profile because of the curvy surface features of the deep-hole profile. The geometric distortion affected the calculation accuracy of the geometric parameters directly. Firstly, the models were established indiscriminately for the deep-hole profile and its plane structure to analyze the space coordinate transformation between each other. Then, the ideas of the cubic spline interpolation and discrete mapping were referred to propose the deep-hole profile correction algorithm based on the discrete mapping considering the precision and speed of the distortion correction comprehensively. The purpose of correcting the deep-hole profile distortion online was achieved through the algorithm. The test precision reached the sub pixel level and the error was less than 0.1 mm.