Aerosols radiation forcing mostly depended on the imagery of complex refractive index. With interferometric spectrometer and Mie theoretics, the theoretical model of interferometric spectrometer method for aerosols complex refractive index was built up in two conditions: similar radius particles and different radius particles, and the detections limit of complex refractive index is discussed at first glance. It shows that the complex refractive index of aerosols particle measured by interferometric interferometer is feasible and promising.