Since shale oil and gas occur in micro-to nano-pores and fractures，researches on pore structure characteristics of shale reservoirs are important to understand the accumulation mechanism of shale oil and gas. There are great differences in pore structure between continental and marine shale reservoirs. In order to analyze their differences in pore structure，several methods including field emission-scanning electron microscopy，CO2 adsorption，N2 adsorption，high-pressure mercury injection，and Soxhlet Extraction，etc. were applied to analyze samples from the lower submember of 3rd member of Eocene Shahejie Formation（Es3l）continental shale in Zhanhua Sag and Longmaxi Formation marine shale in Sichuan Basin.The results show that interconnected honeycomb-shape pores are not developed within organic matter for Es3l shale in Zhanhua Sag. In addition，macro-pores with great pore volume are well-developed，providing good spaces for free hydrocarbon storage and controlling shale oil accumulation. In contrast，interconnected honeycomb-shape pores are well-developed within organic matter for Longmaxi Formation marine shale in Sichuan Basin. Micropores with great specific surface area provide sufficient spaces for absorbed hydrocarbon and control shale gas accumulation.