Abstract: Through field observation,slice,SEM and X-ray diffraction analyses of 41 black shale samples from the Lower Cambrian and the Upper Ordovician-Lower Silurian in and around the Sichuan Basin,the characteristics of reservoir,fracture and pore of shale were studied.There are mainly 2 types of shale gas reservoir:fracture and pore.According to the features of shale gas reservoir,the control of fracture on gas accumulation as well as the nature of fracture,the generation of fracture is classified into 5 degrees:giant,large,medium,small and microfracture.Pores include organic matter(bitumen) pore and/or kerogen network,mineral pores(mineral specific surface,inner,intercrystalline,corrosional and complex-based ones) as well as the pores between organic matter and minerals.Different fracture type,fracture scale,pore type and pore size have different control on shale storage and produce capacity.Pores serve room for gas storage in shale and determine storage capacity.Fractures work as pathways for gas migration in shale reservoir and determine produce capacity.Due to the low porosity and permeability of shale matrix,the generation scales of fracture control the quality of shale gas reservoir.