In 2001～2002,using American Particle Measure Systems (PMS) to make a scientific research during man-made rain enhancement operation in precipitating stratus in May~July in Jilin province,some data were obtained,after making a calculation to these data,the following conclusions were drawn:(1) the macro structure of precipitating stratus in spring in Jilin province is classified into three types : Ns,As op-Sc op and Astra. Different cloud types have different super-cooled water content and cloud droplet amount density,the super-cooled water content and cloud droplet amount density in the cloud of Ns type are the largest,they are respectively 0.2737 g/m3,205.3/L,the second is in the cloud layer of As op-Sc op,0.1693 g/m3,117.5/L,the smallest is in the cloud layer of As tra,0.1054 g/m3,98.6/L.(2)The super-cooled water content in the cloud has a negative correlation with the height of cloud base,and has a positive correlation with the thickness of super-cooled layer. (3)The super-cooled water content and cloud droplet amount density have a basically coincidence with the distribution of the distance to 0 ℃ layer height in these three types of clouds: super-cooled water content and the cloud droplet amount density are the largest in the range of 400~600 meters above 0 ℃ layer height,then super-cooled water content and the cloud droplet amount density reduce rapidly along with the increase of 0 ℃ layer height. (4)The seeding operation rate of precipitating stratus in spring in Jilin province is 86%,the rainfall enhancement potential of these three types of clouds are different,Ns is the largest,up to 41.3%,the second is As op-Sc op,about 28.4%，the smallest is As tra,26.6%.