In order to clarify the sedimentary characteristics, distribution laws and filling patterns of all types of reservoirs in the Permian Fengcheng Formation in Mahu area of the Junggar Basin under the theory of the whole oil and gas system, the sedimentary facies types, basic characteristics, distribution laws, evolution characteristics and filling patterns of all types of reservoirs were systematically studied by using data such as logging, coring and 3D seismic of nearly 50 key wells. The results show that the Fengcheng Formation is a fan delta-lake sedimentary system, with fan delta facies mainly developing subfacies such as plain, inner front, and outer front, and lake facies mainly consisting of shoreline shallow and semi deep lake subfacies. The complete sequence and all types of reservoirs, including various types of coarse-grained conglomerates, medium grained sandstones, fine-grained siltstones, mudstones, and alkaline minerals, are developed. Different subfacies and microfacies develop different types of reservoirs. Different periods of fan delta overlap with each other, forming four fan delta groups in the north, west, south, and east of Mahu Area, mainly composed of distributary channel conglomerate and sandstone sediments, with a gradually expanding distribution range. The western block is mainly composed of contiguous wide and long axis fan deltas, while the eastern is mainly composed of isolated narrow and short axis fan deltas. Under the control of four main factors, It has formed three types of fan deltas under water ingress: retrogressive, composite, and progradational.Three types of mixed sedimentary filling patterns, including under , balanced, and over compensation, have developed together. The systematic study of the sedimentary characteristics and filling patterns provides a basis for deepening the analysis of all types of reservoirs and exploration and development in the field of all oil and gas systems.