A registration method for unorganized point clouds in a structure light 3D scanning measurement is researched and a inheriting and optimizing algorithm is proposed to implement the precise registration of point clouds.The principle of the algorithm is explained,and a mathematical model is established to obtain the rotation and translation parameters.The realizing procedure of the algorithm is described and analyzed.6 groups of point clouds of a car flashing are acquired by a fringe projection 3D scanning instrument,then,the point clouds are registered by the proposed algorithm.Registration errors are analyzed by a multi resolution hiberarchy method,which indicates that the proposed algorithm can implement the precise registration of unorganized point clouds.Experimental results show that the registration standard error is less than 0.10 mm,and the registration time of 2 point clouds is less than 2 s.The required number of iterations are reduced by more than 5 times as compared with that of an ICP algorithm.