The raindrop size distribution was measured for four times during the period from April to June, 1993. The data of measurement were compared with the observation data of filter paper. Based on the two categories of data the basic parameters of raindrop size distribution were calculated and some statistical calculations were made. Using this method the usability of GBPP-100 raindrop disdrometer on field experiments was discussed. The results indicate that: (1) the GBPP-100 can be used on field observation instead of the filter paper during the period that the rainfall intensity slowly changes and is smaller than 160mm/h; (2)there are some obvious differences between the two categories of measurement when the rainfall intensity of shower rapidly changes.