Abstract: In order to study the mechanical characteristics of coal deformation and failure and the evolution of acoustic emission b value of coal in parallel bedding direction, the coal sample in Bijie Mining Area of Guizhou Province is taken as the research object. In this paper, the indoor multi-stage cyclic loading and unloading test is conducted with MTS815. The results show that the elastic modulus exhibits a three-stage change trend, namely, a sharp increase-a slow increase-a sharp decrease; Poisson’s ratio and irreversible strains also exhibit a three-stage change tendency, that is, a slow increase-a gradual increase-a sharp increase. As the stress level increases, the b value of acoustic emission fluctuates somewhat and then stabilizes. When the coal sample is close to rupture, the acoustic emission b value is further reduced.