Deep coal reservoirs are rich in CBM resources and have huge exploration potential, which is the current hot spot of CBM exploration and exploitation research in China. Based on high-pressure mercury intrusion porosimetry and low-temperature N2/CO2 adsorption experiments, the microscopic pore structure characteristics of deep coal reservoirs in the Linxing block were systematically analyzed. The results show that there are obvious differentiation phenomena in the mercury injection and withdrawal curves of deep coal samples in the Linxing block, indicating that the pore connectivity was poor. There are various morphologies of microscopic pores (open pores, semi-open pores, and ink-bottle pores, etc.). Coal samples generally have the most developed micropores and ultra-micropores (<2 nm), which contribute the majority of the specific surface area, followed by macropores and the least developed mesopores. The development of micropores makes the coal have strong adsorption capacity, and the relatively well-developed macropores ensure free gas storage space. However, the low content of mesopores leads to a lack of connecting channels between micropores and macropores. Thus, the fluid output must be improved by high-quality hydraulic fracturing modification to improve its flow conductivity.