In this paper,tentative studies are carried out on the number of annual seismic risk areas,aiming at giving the best estimation of which from the statistical point of view,and giving some reference to the practice of annual earthquake prediction. By R-value evaluation method formulas for calculating the number of annual earthquake seismic risk areas are deduced. Moreover,traditional clustering algorithm is improved to be used to identify earthquake “cluster” area of the close space distance. Through statistics of total number of annual earthquake,earthquake magnitude “cluster area” and “isolated earthquake” in China mainland area during from 1950 to 2019,a variety of statistical distribution models were fitted and tested to determine the reasonable upper limit of the number of risk areas. The results show that the reference values of the number of annual risk areas obtained from the two statistical results are slightly different. The first method is based on the annual occurrence rate of M_S5.5 earthquakes in the east(east of 108°E) and M_S6.0 earthquake in the west(west of 108°E)of mainland China. The reference values of the number of danger areas are 9,which are suitable for the determination of the magnitude of slightly larger earthquakes. The second method is based on the “cluster area” identification results of earthquakes above annual M_S5.0 in mainland China,and the reference value of the number of seismic risk areas is 13,which is consistent with the number used by the China earthquake networks center at present,and is good in practical application in determining annual earthquakes above M_S5.0.