For the problem existing during the calibration between two cameras and a projector，a new self-cali-bration method based on epipolar constraint was proposed． Firstly，according to epipolar constraint theory，epipolar equation was framed by using the feature points on calibration board and their projections on the image planes of two cameras，and the rotation and translation matrixes between cameras were calculated． Then we project multiple cod-ing period fringe images to calibration object to get corresponding coordinate point projected by feature points． Fi-nally，parameter matrix of the relationship between projector and cameras were calculated by the joint efforts． Oneis the two estimation matrixes generated by improved 8 points method，the other is optimization of estimation matrixto objective function by pair and epipolar line． The maximum absolute error is 1. 7 mm，and the maximum relativeerror is less than 0. 18% ． Experimental results show that the proposed calibration method can effectively calibratethe structured light 3D measurement system．