As a high-precision surface shape measurement method，the measurement accuracy of deflection technique not only depends on the calibration accuracy of system parameters，but also is affected by the display surface shape. Especially for the commonly used deflection technique measurement system based on flat mirror reflection model to achieve system calibration，the display surface shape will directly affect the calibration accuracy of system parameters. In order to study the influence of the display surface shape on the measurement accuracy of s stitching deflectometry，this paper firstly presets the display surface shape of different shape variables with the help of the proposed algorithm，and then analyzes its influence on the system calibration accuracy and measurement accuracy. The results show that the display surface shape will reduce the calibration accuracy of system parameters，in addition，an amount of low and middle order errors is introduced into the surface shape measurement results of the components under test. Finally，by comparing with the experimental results，the conclusion obtained by the algorithm is further verified. This study provides a quantitative calculation and analysis method for the measurement error analysis of stitching deflectometry system.