High accuracy calibration is the precondition of the measurement by line st ructured light.To achieve the above purpose,this paper presents a calibration algorithm for line structured light based on planne r target.Firstly,laser line is projected to the target and images are taken at different positions.Then,camera intrinsic parame ters are computed and the target plan function under camera coordinate system is got.Based on the plan function,laser point positio ns under camera coordinate are reconstructed.With more than two images taken from different positions,the laser plan function can be calc ulated by using the linear least square error method. Compared with methods based on invariance of cross ratio,the proposed laser pla ne calibration algorithm can get much more and more accurate calibration points.The algorithm′s availability is assessed by i ts application to a line structured light scanning system. Experimental results show that the mean calibration error by the proposed algori thm is less than 0.024mm and the scanning error is 0.035mm.