Abstract: Jimusaer sag Lucaogou Formation tight oil reservoir lithology is changeable, diverse mineral elements and clastic rock and carbonate rock of the transitional rocks. Dense oil in the region to the source of various storage and source reservoir interbedded characteristics, forming a good source reservoir relationship was set up. In this paper, the study area reservoir pore types in intergranular pore, mainly. Secondly, dissolution pores and micro cracks. According to pressure mercury data can be reservoir pore structure is divided into micro fine throat and throat, but overall has pore throat radius is too small, poor connectivity, strong microcosmic heterogeneity characteristics.