Due to the advantages of fast response, multiple factors metering and easy implementation, the measurement method of light-screen array has been widely used in the measurement of external ballistic flight parameters of barrel rapid-fire weapons. Compared with the separated light-screen array, the integrated light-screen array measurement model has the advantages of simplified parameters, simple model and easy to use. Aiming at the integrated light-screen array measurement model, the structure-related design parameters of the integrated light-screen array measurement model are extracted and the error propagation formula is derived to analyze the influence of different parameters on the measurement error of the projectile flight parameters. Then the simulation model is established in MATLAB according to the analysis result, and the influence law of the vertical angle α, the horizontal angle β, the target distance s and the height difference h on the flight velocity and coordinate measurement errors of the projectile is analyzed. The simulation results show that the vertical angle α mainly affect the projectile ordinate measuring error. and with the increase of α, the ordinate measuring error decreases and the decreasing trend gradually weakens. The horizontal angle β mainly affect the projectile abscissa measuring error, and with the increase of β, the abscissa measuring error decreases and the decreasing trend gradually weakens. The ordinate measuring error, abscissa measuring error and velocity measuring error of the projectile are all affected by the target distance s. The measurement errors gradually decrease with the increase of s and the decreasing trend is gradually weakened. Then the optimization method of structural parameters is given. By increasing angle of light screen structure, the effective target surface detection area will be reduced, and the value range of the optimized vertical angle α and horizontal angle β is from 20° to 30°. Since large target distance is not conducive to transportation, field layout and use, it is more appropriate to choose an optimized target distance s range of 1.5~2.5 m and the height difference is 0 m. According to the error distribution law of projectile flight parameters under the influence of various parameters, typical values are assigned to each parameter in the optimized integrated light-screen array measurement model that the distance between front target and back target s=2 m, height difference h=0 m. The accurate angles of the light-screen are obtained by the calibration experiment using the method of plane fitting that vertical angle α=24.94°and horizontal angle β=24.61°. Then the measurement error distribution of projectile velocity and coordinates in the range of 1 m×1 m rectangular target surface are obtained. The results showed that the measurement error of the projectile is no more than 1.50 mm in horizontal coordinate and no more than 2.10 mm in vertical coordinate. The velocity measurement error is not large, which is 728.70 mm/s. Finally, the live verification test is carried out. Due to the influence of external field environmental factors, the measurement error obtained by the test is slightly larger than the simulation result. The live test results show that the measurement of projectile flight parameters is consistent with the simulation analysis. The maximum error of abscissa measurement is not more than 3.1 mm, the maximum error of ordinate measurement is not more than 4.8 mm, and the maximum error of velocity measurement is not more than 1.1 m/s. The results of the method presented in this paper can provide theoretical basis for the measurement error analysis and theoretical support for the engineering design of light-screen array measurement equipment, and also provide a reference for improving the flight parameter measurement accuracy of barrel weapon projectile.