Fracture is the dominant reservoir for Sudeert structural belt, Hailar basin. Its development directly controls the oil and gas distribution of Sudeert structural belt.Methods:The log information including log analysis, data of geology, mud log as well as production test were collected from Daqing Oil Ltd. Company of China. We described and recorded about 300m core data from 10 wells, and shot about 200 pictures to record the typical fracture characteristics. Fine structure and stratigraphic interpretation had been conducted for the Budate formation in Sudeert structural belt by demarcation on 3D seismic profiles covering an area of 150 km2. Results and conclusions:We conclude that fractures in Sudeert structural belt are in three forms, namely structural fracture, weathered fracture and dissolution fracture, of which structural fracture is the dominant form. The length of fractures is 1~7mm. There are fractures of both low and high angle, the effective fracture angle being 25°~80°. The fracture strike is mainly in North—East and near East—West direction, then NW—SE direction. The fracture development is determined by basement lithology, tectonic forces and stratigraphic erosion. The tectonic setting has a significant influence in fracture formation and transformation in the study area. Basement reservoir fractures distribute vertically in segments, and the main governing factors are different: weathering influences development of fractures on the top; Leaching effect influences development of fractures in the middle; Deep fault influences development of deep fractures. Deep fracture reservoir develops near the deep fault or transformation zone of tectonic stress in the bottom of basin. The deep reservoir is the target zone for oil and gas exploration. The research had a guiding significance in the study of oil and gas exploration in Hailaer basin.