This paper proposes an integrated interference signal detection system based on four-quadrant detectors and wave plate arrays. The Jones matrix is used to establish a model for simulating errors caused by the alignment errors of the wave plate array, and the influence of the alignment errors of the wave plate on the measurement results is analyzed. An experiment is set up for verification and research. The errors introduced by the wave plate increases with the increase of alignment errors. Through experiments, the measurement error range of the quarter wave plate in the range of -20°-20° is 0-13 nm, and the measurement errors of the half-wave plate is 0-2.4 nm. From the above analysis, it can be seen that the quarter-wave plate alignment errors have a significant impact on the measurement results, and the half-wave plate has a smaller impact on the measurement results than the quarter-wave plate. In order to improve the measurement accuracy of the single-frequency interferometry system, the alignment direction of the fast axis of the delay wave plate should be adjusted in place to minimize the alignment errors. The high-performance wave plate should be used as much as possible to reduce the measurement errors. In summary, the wave plate array error model established in this paper provides a theoretical basis for the quantitative analysis of the accuracy of the single-frequency laser interferometer system, and has an important reference for the integration of the single-frequency laser interferometer system and the analysis and elimination of nonlinear errors.