Based on the systematic study of the sedimentary characteristics, sedimentary, micro-facies, and sedimentary evolution of Fuyu reservoir, the following conclusions are obtained. During the deposition of the 4th member of the Quantou formation in southern Songliao basin, the basement sinks stably and slowly, the terrain is gentle and smooth slope. Under the background of lake basin expansion and shallow, river flees into the lake, forms a large shallow lake delta deposition, and divides into two sub-phases, namely, delta plain and delta front. The former delta facies include branch channel, nature levee, crevasse splay, and inter branch channel; the later delta facies include subaqueous distributary channel, subsea natural levee, sub-sea inter branch channel, mouth bar, and distal bar. The shallow delta sedimentary model forms as the result of strong hydrodynamic and the fast water invasion. The direction of the remainder oil is pointed out, and the adjustment for developing project with guiding significance is provided.