This paper introduces the principle of the color 3D laser scanning measurement. The light-plane-equation mathematical model of spatial 3D coordinates is derived. Optimum design for structure parameters of the measuring system is presented, experiments on the optimization of structure parameters were performed, and the structure parameters are confirmed to be the optimum from the experiment results analysis. The measurement error of the system, established on these optimum structure parameters, is less than 0.1 mm in measurement range of 250 mm×200 mm×50 mm.