Based on the annual precipitation data from 48 rain gauging stations in Beijiang River Basin and the method of Thiessen,no-point annual precipitation have been calculated.Combined the classification standard of precipitation,the numeral range of classification which is fitted to Beijiang River Basin has been established.Then based on the verification of the Markov chain characteristics of precipitation,the weighted Markov chain used for predicting the state of precipitation in Beijiang River Basin has been developed.And the results of prediction are satisfied.