Abstract: Based on the data from formation testing, fracture development degree and natural gas component analysis in Dibei gas reservoir in Kuqa depression of Tarim basin, the hydrocarbon distribution and accumulation mechanism are re?recognized. The results show that Dibei gas reservoir is a transitional one between trap?type and continuous tight sandstone gas reservoirs. Natural gas is mainly discontinuously distributed in and around the traps. Diffusion is not the dominant mechanism of gas transport. Gas generated from source rocks flows into reservoirs selectively and continuously fills the neighboring reservoirs in free state along charging points which may be related to fracture development degree in the reservoir. Dibei gas reservoir is classified as a kind of composite tight sandstone gas reservoir according to its special accumulation features. The similar method for exploration of trap?type tight sandstone gas reservoir can be adopted for Dibei gas reservoir