Types of reservoir spaces and micro-pore structure characteristics of early Cambrian Qiongzhusi Fm. and early Silurian Longmaxi Fm. shale gas reservoirs in southern Sichuan basin area were studied by using environmental scanning electron microscopy (ESEM), atomic force microscope (AFM) and adsorption/desorption isothermal method. The results shows that primary pore types of early Cambrian Qiongzhusi Fm. and early Silurian Longmaxi Fm. shale gas reservoir are residual intergranular pores, intercrystal pores, mineral moldic pores, secondary dissolution pores, micropores among clay minerals, organic matter pores. By coupling with ESEM and AFM methods, can objectively reflect the shale gas reservoir pore structure characteristics, and can be complementary to each other. The authors showed that the Qiongzhusi Fm. and Longmaxi Fm. shale gas reservoirs are with great development of micro holes, and provide the large pore volume and surface area for shale gas. But the shale specific surface area and pore volume of Qiongzhusi Fm. are smaller than that of the Longmaxi Fm. shale gas reservoir. The organic carbon content and kerogen type, clay mineral type and content, and thermal evolution degree is the main factors to control the shale gas reservoir microscopic pore structure development, among them, the influence of thermal evolution is the most obvious. In a certain range, the thermal evolution degree and specific surface area, pore volume and clay mineral content has obviously positive correlation. Along with the thermal evolution degree, the organic carbon content andⅡ kerogen content increase, the numbers of the micro-pore, the specific surface area and pore volume are increased