Light screen array is applied to measure firing dispersion in range, and the structure parameters of the array influences the measuring result directly. Based on double-V shaped six-light-screen array, the influence of the structure parameter, the angles of incidence and the impact location to the measurement accuracy of velocity and coordinates are analyzed, and then the error transfer formulas are deduced. The relations between the measurement accuracy of velocity and coordinates to each influence factors are simulated and plotted in MATLAB. The conclusion provided a reference for improving the measuring accuracy and optimizing the engineering design.