An all-fiber spectroscopic filter of rotational Raman lidar system at a laser wavelength of 532.25 nm for temperature profiling is designed for the first time for filtering the weak rotational Raman signal under condition of intense background noise. The spectroscopic filter is optically constructed with three fiber Bragg gratings (FBG) and three optical circulators,and this configuration can separate two rotational Raman signals at the central wavelength of 530.6 nm and 528.8 nm,respectively,for atmospheric temperature retrieval,and block simultaneously Mie-scattering and Rayleigh-scattering signals with a high rejection rate. The spectroscopic filter parameters are designed and optimized by numerical calculation,and the results show that a rejection rate of larger than 7 orders of magnitude for Mie-and Rayleigh-scattering signals can be achieved,which is needed for rational Raman lidar for temperature profiling.