A magneto-optical surface plasmon resonance device (MOSPR) based on Au/Ce∶YIG/TiN structure is proposed. By constructing a three-layer structure which comprises the periodic Au nanodisk array, Ce∶YIG film, and TiN film, the coupling between the Au nanodisk's localized surface plasmon resonance (LSPR) and the TiN/Ce∶YIG interface propagation surface plasmon resonance can be realized, which can significantly reduce the scattering loss of LSPR and enhance the magneto-optical effect. The absolute value of the transverse magneto-optical Kerr effect (TMOKE) of MOSPR reaches 0.21. Using the MOSPR and the strong magneto-optical effect of the magneto-optical oxide to prepare the sensor can significantly improve the figure of merit(FoM)of the LSPR sensor. Based on the TMOKE spectrum for sensing, the sensor's FoM is up to 2192.4586 RIU ^-1. This research provides a new idea for the preparation of LSPR devices with high sensitivity and high FoM.