In order to realize the automatic 3D measurement and reconstruction for a free-form surface,an automatic measuring system for the stereo vision is established and its adopted algorithms such as the nonlinear calibration for the measuring system and the match algorithm for stereo images are investigated. A nonlinear calibration method based on vanishing-point theorem is applied to calibrate the system and the image features of a free-form surface are enhanced by projecting arrays of dots. Then,an array coded algorithm based on direction and distance restrictions is presented to code projecting dots. After setting an original matching point and four original matching directions automatically based on the positions of red points,all other white dots viewed both in two images can be coded by the proposed method and the images in two directions can be matched automatically. The experiments of 3D measurement and reconstruction for a plaster model are undertaken,and the experimental results show that when scale is 0.08 mm/pixel,the square error of 3D measurement for dots is 0.05 mm,which can reach a sub-pixel measurement precision.Moreover,the projective points on a picture can be coded precisely and the matching between two images can be performed effectively by the array code method based on direction and distance restrictions.