The effect of SiO2 film on the Rayleigh wave characteristics in ZnO/IDT/Si structure is analyzed by 3Dfinite element method (3DFEM), including the phase velocity (vp), electromechanical coupling coefficient (k2), and temperature coefficient of frequency (τf). The results show that, for the Rayleigh waves excited in ZnO/IDT/Si structures, the maximum k2 of 2.38% is obtained as hZ/λ=0.44, associated with vp of 3 016 m/s and τf of -32.94×10-6 ℃-1. The k2 values of Rayleigh waves in ZnO/IDT/SiO2/Si structures are increased significantly by introducing the bottom SiO2 layer. As hZ/λ=0.44 and hsb/λ=0.25, the coupling coefficient k2max equals to 3.41%, with vp and τf of 2 801 m/s and -11.43×10-6 ℃-1, respectively. For the Rayleigh wave devices based on ZnO/IDT/SiO2/Si structures, the introducing of top SiO2 layer results in the increasing of phase velocity, while the decreasing of the coupling coefficient with the increase of the thickness of SiO2. And the k2 of 2.61% is obtained as hZ/λ=0.44, hsb/λ=0.25 and hst/λ=0.25, associated with vp of 3 036 m/s and τf of 18.44×10-6 ℃-1. All of the results indicate that the introducing of double SiO2 layers can effectively increase the phase velocity, electromechanical coupling coefficient and realize the temperature compensation of the Rayleigh wave devices. Thus the proposed structure can be used to develop SAW device with high electromechanical coupling coefficient, high temperature stability and low cost.