 The optical displacement calculation formula for the dual Walliston prism was derived from the wave normal tracing method. This formula was then compared to captured photographs to confirm its accuracy. Additionally, the relationship between the maximum incident aperture, incident angle, and incident surface angle was given when plane and spherical waves were incident on the prism group. Furthermore, the aperture utilization of a novel static birefringent Fourier transform imaging spectrometer based on dual Walliston prisms was analyzed. Finally, the relationship of aperture utilization with the incident surface angle, incident angle, and prism's air gap thickness was given. This article was authored by Xiang Zhixiang, Jingping Zhu, Li Chenhuang, and others.