Using the boundary layer wind profile radar (WPR), a stratiform cloud precipitation event was observed and studied, which occurred in Bayinbluke in the central part of Tianshan Mountain from 22:00 BT 8 August to 04:00 BT 9 August 2012. The spectral parameters were obtained by calculating the data of vertical velocity power spectrum. The height of 0℃ layer evaluated by the change characteristics of spectral parameters is from 1100 m to 1900 m. By analyzing raindrop size distributions from 600 m to 1100 m, it is found that different size reflectivity depends on the concentrations of mid sized particles and large sized particles. The tempol and spatial trends of rainfall intensity and water content evaluated by raindrop size distributions are the same as the trend of reflectivity evaluated by the power spectral density. By analyzing the relationship between raindrop intensity and reflectivity, the equation is established: Z=76.5I1.6.