Abstract: Using TAW-2000 servo testing machine, the uniaxial compression and shearing experiments were tested for mudstone, fine sandstone and gritstone, and at the same time, the Germany VallenAMSY-6 acoustic emission signal acquisition system was used for collecting the acoustic emission signals. The difference and evolution laws of acoustic emission waveform under two loading modes and at different stages of loading were analyzed by adopting fractal methods. And the results show that the fractal box dimension of acoustic emission during the process of uniaxial compression test is generally greater than that during the process of shear test, and in addition, waveform of uniaxial compression test is more complex than that of shear test. Besides, with the increasing of stress, the fractal box dimensions of acoustic emission signals of uniaxial compression test gradually arise, however, the fractal characteristics of shear test do not have similar law.