Abstract: In order to discuss the different mineral affected to the crack structure features of the lignite, with three large depression major lignite seams in Erlian Ba sin as the object, with the applications of the full rock and clay X-ray difraction, scanning electron microscope, cryogenic adsorption, pressure mercury test and other a nalysis and test means, the mineral features and crack features of the samples were analyzed and the minerals affected to the crack structures were discussed. The re sults showed that the minerals of the lignite in the three depression major seams of Erlian Basin would be clay mineral and quartz mainly. Other mineral contents would be low. The clay minerals would be kaolinite mainly. The minerals mostly were the organic concomitants and were dispersedly distributed in the organics. In the study ar ea, the lignite would have three types sorption and desorption delay curves and the distribution of the borehole volume would be the double peak development mainly. T he fractal dimension would be 2.473 ~ 2.616. The fractal dimension of the adsorption borehole would be higher than the fractal dimension of the seepage borehole gene rally. The fractal dimension of the crack was mainly controlled by the adsorption borehole. The fractal dimension of the crack would have a negative correlation to the h umus contents and clay minerals and would have a positive relationship to the inertinite contents, ash yield and quartz contents. The organic maceral and mineral conte nts of the coal would be affected to the crack fractal dimension and mainly depended on the humus contents and quarts contents individually.