Aiming at the raindrops imaging degradation of precipitation micro-physical characteristics sensor (PMCS), and considering the defocus blurring due to light source, a raindrop images restoration method based on point spread function (PSF) is proposed. Sharp images of raindrops can be obtained by the disk function. The radius of defocus blurring and thresholds of images binarization are determined by the calibration experiment of a series of glass balls, which have similar optical features with raindrops. The field experiment results show that the images restoration method can precisely correct the raindrops size and their distribution, the raindrop size distribution and rainrate measured by PMCS are in good agreement with the measurements of laser disdrometer. The application of images restoration method can promote the performance of raindrop size distribution, and other micro-physical characteristics measured by PMCS.