为研究不同变质程度煤体微孔孔径多重分形的特征，根据低温液氮吸附实验数据，运用多重分形理论对4种不同变质煤体样品微孔的多重分形特征、以及孔隙特征与变质程度之间的关联展开研究。结果表明：4种煤样微孔均具备了多重分形的典型特征，变质程度越高煤样的微孔分布非均质性越强，其微小孔拥有更大的比表面积，将会为瓦斯气体提供更多的吸附位，拥有更大的解吸量；4种煤样的微孔孔径多分布在孔隙空间较为狭小的区域中，约为7~9 nm；微孔结构在弱变形作用下的非均质性明显，在此区域内，较大的孔径分布均一；但从整体看，其连通性与变质程度关系不明显且孔隙以聚集和分布不均匀为主导。

In order to study the multi-fractal characteristics of micropore pore size of coal with different metamorphic degrees, according to the low temperature liquid nitrogen adsorption test data, the multifractal characteristics of micropores of 4 different metamorphic coal samples and the correlation between pore characteristics and metamorphic degrees were studied by multifractal theory. The results show that the micropores of 4 coal samples have the typical characteristics of multifractality. The higher the metamorphic degree is, the stronger the heterogeneity of the micropore distribution of the coal sample is. The micropores have a larger specific surface area, which will provide more adsorption sites for gas and have a larger desorption amount. The micropore pore size of 4 coal samples mostly distributed in the narrow area of the pore space is about 7-9 nm; the micropore structure has obvious heterogeneity under weak deformation. In this region, the larger pore size distribution is uniform. However, on the whole, the relationship between connectivity and metamorphic degree is not obvious, and the pores are dominated by aggregation and uneven distribution.