The measurement accuracy of the three-dimensional (3D) coordinate measuring system based on laser multi-lateration is influenced by its layout. In previous study, the system′s layout is optimized for the tri-rectangular pyramid layout by theoretical analysis of the non-target self-calibration model. On this basis, through error analysis of the linearized measurement model of the system, it is found that the optimal layout, that is the tri-rectangular regular pyramid layout, is obtained, when the condition number of the coefficient matrix of the measurement model achieves minimum. Simulation results show that the tri-rectangular regular pyramid layout can efficiently ensure the accuracy of the system.