Abstract: In order to study the characteristics of the whole pore structure of coal with different metamorphic degrees, six groups of coal samples were selected for coal vitrinite reflectance test, mercury intrusion test and low temperature nitrogen adsorption experiment. And we combined with mercury intrusion experiments and low temperature liquid nitrogen adsorption experimental data for systematic analysis. The results showed that: the cut-off points of the two experiments were BD01 （38.4 nm）, PMBK07 （46.8 nm）, HBM03 （35.0 nm）, ZZ01 （45.8 nm）, SHE02 （34.6 nm）, FH03 （23.8 nm）; with the increase of metamorphic degree, the total pore volume of coal sample presents a trend of “high-low-high”, and the control effect of visible holes and macro-pores in coal is obvious; the micro-pore contributes the maximum to the total pore surface area, and the total pore surface area exhibits a type of “W” change trend, reaching the maximum value in the anthracite FH03（R_o,max=3.77%） stage; the relationship between the pore morphology of coal and the degree of metamorphism is not obvious, and the pore of coal sample is mainly open hole and the pore connectivity is better. In the anthracite FH03, there are many parallel plates with open ends in the pores.