Understanding the shear characteristics of hard structural planes is crucial to the stability of deep engineering. In this study, a series of laboratory-prepared cubic granite containing hard structural plane were subjected to true triaxial shear testing by experimental apparatus. The results indicate that the increase of lateral stress and normal stress will affect the deformation of the granite specimen and increase the shear strength. Additionally, the macroscopic and microscopic failure modes of the specimen are related to the lateral stress. Both shear fracture and tensile fracture were observed on the hard structural failure plane by scanning electron microscope (SEM). The acoustic emission (AE) ringing count signal collected during the test is closely related to the degree of fracture of the specimen. The signal is relatively low at the initial stage of the test, and it increases significantly when the signal approaches the peak strength, reaching the maximum at the peak strength.