Abstract: The reservoir characteristics and influential factors of Wengxiangqun formation are studied based on analysis of outcrop observation,the testing materials of ground samples in combination with drilling materials in Majiang area.The results shows the sandstones of Wengxiangqun formation is the reservoir with middle - low porosity and permeability, the sandstone with a high degree of compositional maturity consists mainly of Lithic - quartz sandstone and quartz sandstone, the pores of the reservoir are mostly primary intergranular pores and intergranular dissolution pores,the characteristics of the pore structure is moderate pore-throat composition.Ground samples average residual oil saturation is 10.07%and it is generally low.Distribution of residual oil saturation is controlled by palaeohigh and lithologic change. The character of reservoir is mainly formed by terrigenous clastics composition and diagenesis,the structure and content of terrigenous clastics composition are direct factors affecting reservoir physical property,compaction and cementation of diagenesis mainly make reservoir varied,while denudation makes reservoir physical property become better.