The obvious and well preserved fossil hydrographic net of Songhua Jiang in the Wurhuli hilly district of the Three-River plain shows that the Songhua Jiang once flowed near Pujin southeastward through the Naoli River into the Wusuli Jiang during middle Pleistocene. From Bpipleistocene to early Holocene epoch, due to uplifting of Neotectonic movement in the Fujin-Erlongshan area, the Songhua Jiang drainage sys-tem underwent an adjustment, it flowed northeastward into the Heilongziang near Jiejinkou.