Abstract: The pore development characteristic of limestone is an important factor in understanding the adsorption gas reservoir and migration in limestone. In this paper, the typical geological section of coal-bearing series of the late Carboniferous epoch Taiyuan formation in Huainan coalfield is taken as the research object; the samples of different layers of limestone are collected from the upper and lower layers according to the stratigraphic sequence. The specific surface area and pore size distribution characteristics of limestone samples are observed by using the low temperature nitrogen adsorption method combined with scanning electron microscope (SEM). The results show that: the pore types of limestone in different layers are mainly secondary intergranular micro-pores, followed by super micro-pores, dissolved geodes and dissolution cracks; the specific surface area and total pore volume of limestone samples in different intervals are positively correlated with the total nitrogen adsorption, i.e., with the increase of specific surface area and total pore volume, the nitrogen adsorption capacity is enhanced and the porosity development degree is increased; the average pore radius decreases with the increase of the outer surface area; the pore structure of each sample is dominated by mesopores, followed by micropores and contains a small amount of macropores; good connectivity between pores, is conducive to oil and gas, water storage and migration.