In the paper, we have discovered the abnormal area distribution features of maximum variation values of ground motion parameter uncertainty with different probabilities of exceedance in 50 years within the range of 100°~120°E, 29°~42°N for the purpose to solve the problem that abnormal areas of maximum variation values of ground motion parameter uncertainties emerge in a certain cities and towns caused by seismicity parameter uncertainty in a seismic statistical region in an inhomogeneous distribution model that considers tempo-spatial nonuniformity of seismic activity. And we have also approached the interrelation between the risk estimation uncertainty of a site caused by seismicity parameter uncertainty in a seismic statistical region and the delimitation of potential sources, as well as the reasons for forming abnormal areas. The results from the research indicate that the seismicity parameter uncer- tainty has unequal influence on the uncertainty of risk estimation at each site in a statistical region in the inhomoge- neous distribution model, which relates to the scheme for delimiting potential sources. Abnormal areas of maximum variation values of ground motion parameter uncertainty often emerge in the potential sources of Mu≥8 (Mu is upper limit of a potential source) and their vicinity. However, this kind of influence is equal in the homogeneous distribu- tion model. The uncertainty of risk estimation of each site depends on its seat. Generally speaking, the sites located in the middle part of a statistical region are only related to the seismicity parameter uncertainty of the region, while the sites situated in or near the juncture of two or three statistical regions might be subject to the synthetic influences of seismicity parameter uncertainties of several statistical regions. In the paper, we have discovered the abnormal area distribution features of maximum variation values ​​of ground motion parameter uncertainty with different probabilities of exceedance in 50 years within the range of 100 ° ~ 120 ° E, 29 ° ~ 42 ° N for the purpose to solve the problem that abnormal areas of an variation in ground motion parameter uncertainty of emergencies in a certain cities and towns caused by seismicity parameter uncertainty in a inhomogeneous distribution model that considers tempo-spatial nonuniformity of seismic activity. also approached the interrelation between the risk estimation uncertainty of a site caused by seismicity parameter uncertainty in a seismic statistical region and the delimitation of potential sources, as well as the reasons for forming abnormal areas. The results from the research indicate that the seismicity parameter uncer - tainty has unequal influence on the uncertainty of risk estimation at each sit ein a in a statistical region in the inhomoge- neous distribution model, which relates to the scheme for delimiting potential sources. Abnormal areas of maximum variation values ​​of ground motion parameter uncertainty often emerge in the potential sources of Mu ≧ 8 (Mu is upper limit of a potential source) and their vicinity. However, this kind of influence is equal in the homogeneous distribu- tion model. Generally speaking, the sites located in the middle part of a statistical the sites are only related to the seismicity parameter uncertainty of the region, while the sites situated in or near the juncture of two or three statistical regions might be subject to the synthetic influences of seismicity parameter uncertainties of several statistical regions.