Abstract: Based on attenuation law and space-time propagation characteristics of seismic ground motion, we use recorded time histories from adjacent monitoring stations to make near real-time interpolation calculation in a 1 km×1 km grid, and correct ground motion parameters according to the site effects. Taking the 12th February, 2014 Yutian M_S7. 3 earthquake as an example, we calculated seismic time history in each grid near the epicenter, and then plot peak ground motion contour maps with 8 s intervals continuously. Finally we showed spatial distribution of peak ground motions (PGV and PGA) of this earthquake. The results show that, influenced by site conditions as well as soft ground soil and shallow groundwater level, ground motions in the region from eastern Yutian County to northern Minfeng County were amplified obviously, which were well consistent with field survey results. On the conditions of uneven distribution of strong ground motion observation stations, the method can be used to describe the characteristics of earthquake ground motions, and reflect the characteristics of strong ground motion in disaster areas objectively.