Abstract: Aiming at the specific complex conditions of Su 53 blocks, such as less marker beds, big variance of rock formation in fluvial facies, less drilled well and developed microstructures, the research of horizontal well into target technology has been carried out. By comprehensively using the auxiliary judgment methods of azimuth change rule and formation apparent thickness difference, and the marker beds method, the top boundary depth of marker beds can be accurately predicted, the hole deviation angle can be timely controlled and then the horizontal well can be accurately into the target. The research results have been successfully applied in Su 53 block, which improves the drilling success ratio of horizontal wells and provides reference and guidance for geosteering of horizontal wells sidetracking of similar type gas reservoirs.