Abstract: In order to study the influence of coal thickness on acoustic emission characteristics and pre-peak damage characteristics of coal-rock combination bodies during deformation and fracture, uniaxial compression acoustic emission tests were carried out for three coal-rock combination bodies with coal thickness of 20mm, 33.33mm and 60mm respectively. The results show that with the increase of coal thickness, the uniaxial compressive strength and acoustic emission peak count of coal and rock composite decrease, and the relation between coal thickness and acoustic emission peak count satisfies exponential function. The failure duration of composite increases with the increase of coal thickness. The variation of ae cumulative count can be divided into slow growth stage, rapid growth stage and peak acoustic emission stage. In the first two stages, the growth rate of ae cumulative count is positively correlated with coal thickness, and in the last stage, it is negatively correlated. The pre-peak damage evolution of the composite body can be divided into three stages: initial damage, stable damage development and sudden and unstable damage development. The relationship between damage variable and strain satisfies power exponential function, and with the increase of coal thickness, the corresponding peak strain increases when D=1.