Abstract: According to the high mining speed of modern mines in China, the fracture characteristics of rock mass under different uniaxial loading rate was systematically analyzed. Based on the geological condition of deep rock mass in Jining area, the optimum mortar composed of 425 Portland cement, sand with particle size less than 2 mm, gypsum, water and high efficient water reducer was used, which had the mechanical properties similar to real rock mass was ascertained. Applying the triaxial rock test system of coupled stress-seepage and PCI-2 real-time monitoring system of AE, the fracture process of specimens of large size under biaxial loading was studied, the evolution law and AE behavior feature of specimens with prefabricated single and double cracks under different loading rate were obtained. The results show that the specimen with single crack is easy to develop anti-wing crack due to shear stress when loading rate is 1.5 kN/s; the bigger of rock bridge angle between cracks, the easier to accelerate fracture of specimen and the less AE events appear, which shows the fracture mutation of rock mass.