Integrated fiber-optic gyroscopes have considerable application prospects in miniature weapon systems and commercial domains. The integrated optical transceiver module, which is a key component of the integrated fiber-optic gyroscope, incorporates the functionalities of the light source, detector, and coupler. The coupling shift in the optical path can significantly affect the optical coupling efficiency and average wavelength, which in turn affect the zero bias and scale factor of the fiberoptic gyroscope. In this study, theoretical modeling of the spatial optical path is conducted, and the overlap integral method is used to calculate the coupling efficiency. The BeamProp method is utilized for simulation analysis to determine the coupling loss and average wavelength drift under various coupling displacements. Comparative experiments are conducted to verify the theoretical and simulation results. The findings indicate that the coupling shift in the y-direction has the most significant effect on the coupling loss, whereas the z-direction shift has the most substantial influence on the average wavelength drift. Data for the average wavelength drift at different coupling losses are provided, offering guidance for the coupling and optimization of the optical path of the integrated optical transceiver module.