Abstract: Based on the fault tree analysis method, Seismic spatial distribution functions in North China seismic belt are determined.Geological factor of each potential earthquake source in North China seismic belt is calculated by using the relation between the fault length, the surface wave magnitude, the seismic moment and the moment magnitude.Meanwhile, the active factor of each potential earthquake source is determined by maximum likelihood method, the Bayesian prediction method, and the seismicity method. Considering all the active actors, the fault tree of spatial distribution function for probabilistic safety evaluation is built, and thus the seismic spatial distribution functions in North China seismic belt is obtained.In addition, the seismic risk of one test site is calculated by the newly achieved Functions.