The aperture acts as a limiter of the imaging beam in the spatial domain and is used in a wide range of applications in optical systems.In digital speckle pattern interferometry systems,aperture is usually used to limit the spatial frequency of the object light to facilitate the subsequent signal demodulation of the target to be measured.Ideally,the central position of the aperture should coincide with the optical axis,and the surface should be perpendicular to the optical axis.However,the center of the diaphragm often deviates from the optical axis due to the adjustment accuracy during the field use,or an eccentric diaphragm is used due to structural design problems.In this paper,based on the Fourier transform characteristics of spatial beams,the influence of the deviation of the aperture center from the optical axis on the spatial spectrum of object light and digital speckle pattern interferometry is investigated and experimentally verified.Theoretical and experimental results are consistent.The results given in this paper has theoretical guiding significance for the design of key parameters of digital speckle pattern interferometry system.