We propose a millimeter-wave radar and dual-wavelength lidar combined model for the microphysical and optical properties of water cloud particles. On this basis, we build the relationships of the effective radius and reflectivity-extinction ratio, as well as reflectivity-backscattering ratio of water cloud particles. Assuming the effective radius of the cloud droplet at the reference height and the lidar ratio at the next range gate, we can obtain the backscattering coefficient at the boundary value using the effective radius and backscattering coefficient inversion errors by dual-wavelength as constraints. Moreover, we employ Fernald backward integration method for the inversion of the aerosol profiles under water cloud conditions. The correlation coefficient between the simulated effective radius and that after algorithm processing is 0.98, and the correlation coefficient of the dual-wavelength backscattering coefficient is 0.81. The case studies indicate that this method can give rise to better inversion continuity of aerosols under water cloud conditions and a relatively accurate backscattering coefficient.