The refractive index is important for studying aerosol. A new method is proposed to retrieve the refractive index of aerosol by using Aethalometre、Optical particle counter and Integrating Nephelometer.The absorption coefficient and scattering coefficient are measured with a Aethalometre and Integrating Nephelometer. and at the same time

the number density distribution of aerosol particle is measured by Optical particle counter with nominated radii

Mie theory is used to set up the relationship among the refractive index 、size distribution、absorption coefficient and scattering coefficients. Then

a curve of absorption coefficient and scattering coefficient can be calculated with different refractive index. Actual value of refractive index can be decided with the measurement absorption coefficient and scattering coefficient by Aethalometre and Integrating Nephelometer. The comparisons with other instruments show that this method is satisfactory. The character of refractive indices of aerosol particles retrieved in Xiamen with the proposed method are discussed at last..