In order to solve the sensitivity problem of the temperature in the solution refractive index measurement, a new scheme for refractive index sensing with cascaded Long-period Grating(LPG) and Fiber Bragg Grating(FBG) was presented by using insensitive to refractive index of fiber Bragg grating.The results show that the two resonance wavelength of cascaded fiber grating possesses linearity with the change of temperature, however, only one resonance wavelength shift with the change of the solution refractive index.Thus by using the cascaded fiber grating, we can simultaneously measure the refractive index and temperature, to compensate measuring error by temperature variations.