A systematic research of the late Quaternary activities of the middle part of Kouquan fault was done by conducting a 1：50000 geologic mapping combining with remote sensing interpretation of spot image,field validating and chronology research of the area.The study suggests that the middle part of Kouquan fault has strong activities since late Quaternary which control the tectonic evolvement of the nearby mountains and Datong basin.The recent activity of this fault has faulted the sand and gravel of T1 terrace and the lower part of dark loessial soils over the terrace north of Chanfang village.The maximum vertical faulted value is over 3m in the part between Xiaoyukou village and Louzikou village,and to the south to Dayukou village and the north to Emaokou village,the faulted value decreases to 0.5m and 0.25m respectively.Based on the recent faulted landforms,we conclude that the recent activity of the area happened in the ages between 7.71kaBP to 3.00kaBP.We also discuss the activity on the basis of the former researches.[著者文摘]