The breakage model including two - body equal - volume birth function and two - body powerlaw death function was used in the agglomeration and breakage population balance model . The new analysis method made the population balance model fit crystal size distribution very well . The results of crystallization kinetic experiment by using MSMPR precipitator has proved that the new method is correct. So a reasonable method of study on agglomeration and breakage of reactive precipitation of procaine ben-zylpenicillium can be obtained .