Existing static wedge interferometer can not achieve zero optical path difference, thereby affecting the accuracy and speed of spectral inversion. Therefore, a method of achieving zero optical path difference by improving the wedge structure was put forward. By improving the structure of the inclined surface, the wedge can be achieved on the incident light interference signal which contains zero optical path difference. By deducing and analyzing the optical path difference of the arbitrary wedge position, and the formula of spectral inversion was deduced. Using Zinc Selenide(ZnSe) materials design and processing of the wedge, interference signal and the optical path difference was simulated, and the process of spectral inversion was simulated. The wedge was analyzed by experiments which used 10.64 μm laser. Result shows that the interference signal clarity, optical path difference can reach 1 450 μm, and the relative error of experiment is 0.1%.