L625 4-wavelength dual Raman-Mie lidar was used to detect elastically Mie backscattered light at emitting wavelengths (532 and 355 nm) emitted by one Nd:YAG laser, and the nitrogen Raman light (607 and 386 nm) inelastically backscattered by nitrogen molecules at Hefei (117.3 degrees F, 31.9 degrees N), China from 2007 to 2013. From the four return signal profiles, highly accurate aerosol extinction and backscatter coefficients, lidar ratio, Angstrom exponent, and aerosol Junge exponent can be determined. Furthermore, with a priori assumption of the real part of complex refractive index n(r) = 1.50, the profiles of more aerosol microphysical parameters can be retrieved with their respective errors in the free troposphere, such as the imaginary part of the refractive index, Junge number density coefficient, and particle mass index. The profiles of aerosol microphysical parameters were obtained for 179 nights. Their variation and statistical features were discussed. (C) 2019 Optical Society of America