We simulated the depolarization signal in adiabatic water clouds due to the occurrence of multiple scattering when measure the microphysics characteristics using depolarization lidar. The number density of the adiabatic water clouds is constant in vertical direction. The liquid water content and the effective radius are nonlinear increasing with the height, and the varying rule is controlled by the barometric pressure, temperature, and the thermodynamic formulas. The wavelength of the lidar is chose as 0.355 μm. From the computing results, we can see that depolarization ratio increasing with the depth of the cloud, and it increasing with the receiving field of view angle, but it has great difference with the homogeneous cloud. The effective radius of the cloud with clouds base height is 2 km are less than the one with cloud base height is 1 km, so the depolarization ratio is also small with same number density and observation conditions.