Abstract: Aiming at whether the coal seam water injection will reduce the lump coal production rate of anthracite fully mechanized caving face, the indoor uniaxial compression test method is used to study the compressive damage of the anthracite sample with natural moisture content and saturated water content under controlled compression conditions. The distribution law of the broken block degree is as follows: (1) Water injection reduces the peak strength and elastic modulus of anthracite, enhances the plastic fluidity and residual strength after the anthracite peak; (2) Water injection causes the coal to be damaged by pressure After the block distribution is more uniform, it indicates that the coal seam water injection can reduce the large coal volume in the fully mechanized caving mining, increase the medium coal mass, and the small block and the amount of pulverized coal basically have no change; (3) Anthracite compression crushing block The degree-mass distribution conforms to the fractal law, and with the increase of the water content of the water injection, the fractal dimension of the block-mass distribution after the sample is broken is reduced, that is, the uniformity of the coal fracture block is improved. The research results show that the implementation of coal seam water injection in the fully mechanized caving face can not only soften the coal body, increase the top coal release rate, but also increase the medium-size coal volume with high sales price, which is of significance to improve the economic benefits of anthracite production enterprises.