Abstract: Regional distributions of the seasonal variations of precipitation and rainstorm which are closely related to the designs and operations of water resources and hydroelectric projects are studied,including seasonal variations of the rainstorm elements:means of ten day precipitation and maximum 1d rainfall,inter-annual variation of rainstorm,depth-area-durat ion relationship,etc..The map of the seasonal concentration coefficient of precipitation is shown,and the similarities and differences for the seasonal variations among precipitation,ordinary rainstorm,and rare rainstorm are also discussed.