This paper is based on the field investigation of the geological disaster that caused by the 5.12 Wenchuan Earthquake in Qingyang City and Pingliang City, Gansu Province. It is found that the earthquake-induced collapses and landslides are charcterized by small type and large number and are mainly distributed at the of the edges of modern erosion ditch; The earthquake-induced landslides distributed in the tableland surface, gentle slope hills and tableland of the valley, is consistent with the cave dwelling and the engineering construction. Although this earthquake has not caused large or medium-sized landslip, we cnnont neglect the influence of its natural environment, which may change the micro physiognomy and increase the soil erosion etc. in the next few years. It indicates that it will cause more serious gravity erosion once the earthquake intensity over degree Ⅳ in the Loess Plateau area, which slightly has the difference from the former general recognition. For the Loess Plateau that is one of the frequent earthquake areas in China, effects of the earthquakes need to be considered when the genesis of soil erosion discussed.