In order to provide a theoretical reference for the rational application of tilted long period fiber grating in the field of refractive index sensing, the variation rule of effective refractive index and wavelength drift of resonant wave under different cladding modes and different cladding radius are simulated by optical simulation software. The simulation results show that the effective refractive index of each cladding of the grating increases with the increase of the refractive index of the environment, and higher order cladding modes with smaller radius have higher sensitivity. According to the variation rule of the wavelength shift of the resonant wave and the refractive index of the environment, different parameters can be selected in practical applications to meet different sensitivity requirements.