Abstract: Abstract: After the uniaxial compression experiments and acoustic emission monitoring were carried out on coal-concrete connectors with different water content, and the mechanical properties and acoustic emission characteristics of connectors were explored. The following conclusions can be drawn: 1) water has a significant influence on the compressive stage, failure stage and post-peak stage of the characteristic cracks of the stress-strain curve of the coal-concrete joints. The presence of water reduces the cohesion between samples, reduces the brittleness and enhances the plastic shape.2) With the increase of water content, the failure mode of coal rock combination changes from tensile failure to shear failure, and the plastic deformation is significant. 3) The acoustic emission characteristic curve corresponds well to the stress-strain curve. With the increase of water content, the peak position of acoustic emission AE count is advanced, and the structural failure of the composite sample occurs in advance. The peak value of AE count gradually decreases and the brittleness of the composite sample decreases. The research results have a certain reference value for the stability of the connection between coal pillar dam and artificial dam of coal mine underground reservoir.