A magnetoelectric surface acoustic wave (SAW) resonator based on FeGa alloy magnetostrictive substrate has been investigated in this paper. First, the ScAlN piezoelectric film was deposited by RF reactive magnetron sputtering on FeGa alloy magnetostrictive substrate and the oneport SAW resonator was fabricated. Then the structure analysis of ScAlN thin films was carried out by XRD, SEM and AFM. Finally, the S11 parameter and group delay were measured by the vector network analyzer and microwave probe station. The results show that the ScAlN thin film has a columnar growth and a high (002) orientation, and the film surface roughness (RMS) is about 2.36 nm. When the thickness of the ScAlN piezoelectric film is 0.7 μm and the wavelength is 15.74 μm, the resonant frequency of SAW resonance is 218.75 MHz, the phase velocity is 3 443 m/s, and the electromechanical coupling is 0.06%, which is in good agreement with the COMSOL simulation results.