Based on consulting an ample historic data about Yinchuan-Pingluo M8 earthquake in1739 and combined with the former studies on some earthquakes in the Yinchuan Plain the distribution of the earthquake intensity and the characteristic of the earthquake disaster are researched. The result indicates that the earthquake was caused by the Helanshan fault in the the eastern piedmont of Helan Range, the most destroyed area lies its southeast area Yinchuan- Pingluo region, where is identical with the Quaternary sedimentation center of Yinchuan rift and affected mostly by the engineering geological conditions. The characteristic of this seismic disaster have important significance and active effects on the city layout and decreasing earthquake disaster in the future.