Based on the outcrop features and conventional petrophysical properties, the reservoir characteristics of T₁j₂ of Zhaigouwan structure in eastern Sichuan are studied. The result shows that the reservoir rocks are mainly composed of crystal grain dolomite and particle dolomite. The reservoir spaces are mainly intercrystal pores and dissolved pores.The reservoir properties are poor. The reservoir types are fracture-pore and pore-fracture. Reservoirs mainly developedin T₁j₂² along longititudinal direction, less in T₁j₂1 and partly in T₁j₂³. Reservoirs of T₁j₂² developed well in Zhaigou 2 well and Zhaigou 4 well, while reservoirs of T₁j₂¹ developed well in Zhaigou 4 well. Sedimentation not only controls the development and distribution of reservoir, but also affects the basic pattern of reservoir and the type and intensity of diagenesis. It is the dominated factor controlling the reservoir development. Diagenesis determines the reservoir space and reservoir performance, and directly influences the forming and evolution of pore space. Tectonism provides conditions for the above activities.