Knowledge about the full range of pore sizes in a coal seam is important to investigate the gas storage capacity and pore connectivity for the exploration and development of coalbed methane. To better understand the pores in coal, this study integrated the experimental approaches, such as the separation of coal macerals, petrological analysis, low-temperature nitrogen adsorption, CO2 adsorption, and mercury intrusion porosimetry, to quantitatively characterize the pore geometry of anthracite collected from the southern Qinshui Basin, China. The full spectrum of pore size distribution (PSD) was compiled based on measurements obtained by the adsorption and porosimetry techniques. The results show that vitrinite in anthracite exhibits a unimodal PSD dominated by micropores, under the condition that the interparticle void influence was excluded. The absence of meso- and macropores indicates a lack of connectivity between micropores and fractures. Micropores in vitrinite have a specific surface area of more than 350 m(2)/g, accounting for >98% of their total specific surface area and providing significant spaces for coalbed methane storage. A numerical fitting model was proposed to quantitatively predict the PSD, which can be further used to estimate the diffusion coefficient or permeability of coalbed methane. It was also found that if the sample size decreased from 40 to 120 mesh, there was no obvious increase in pore volume, suggesting that vitrinite mainly contains no closed pores. Furthermore, pore analyses using the samples with different maceral compositions showed that vitrinite content has a positive correlation with PSD, especially for micropores. Along with minerals, inertinite largely contributes to the volume of mesopores. With an increase in inertinite and mineral matter contents, the specific surface area decreases, which may affect the coalbed methane adsorption capacity and in situ gas content of coal seams.