“…It has been used as an important means to study the damage and fracture mechanism of rock materials. Brich [1] found that the longitudinal wave velocity of the rock was linearly positive with the density of the rock; Simmons [2] analyzed the CaO content on the impact of changes in velocity based on this theory and obtained empirical formula; Walsh et al [3], studies have shown that in the compaction process, the ultrasonic wave velocity in the rock increases with the load increasing and decreases with the load increasing in the expansion stage; Willis's [4] studies have shown that when ultrasound wave propagation in fractures, will produce reflection, refraction, scattering and other phenomena, and the form of propagation is accord to the ultrasonic wave length and crack linear size; Freund [5] studied the vertical and transverse velocities of sedimentary clastic rocks with porosity, clay content and confining pressure; Khaksar [6] found that the compressional and shear wave velocities of dry gas-bearing sand layers are approximated by the power function. Pei Zhenglin et al [7], presented the the change rule and the fracture properties of relations among the first wave, the coupling wave and the coda waves, through the comprehensive study of the full wave waveform of the ultrasonic penetration signal of the ideal fracture system in the rock; Chen Gengye et al [8], derived the relationship between damage parameters and attenuation coefficient and use energy method for basalt damage and stress attenuation test experimental study based on the analysis of rock fissure damage sound attenuation; Zhao Mingjie [9] proposed the equivalent model by using the relationship between rock deformation characteristics, void ratio, equivalent elastic parameters and wave velocity and attenuation, and established the theoretical relationship between sound velocity and attenuation and stress during loading and unloading; Shi Jinjin et al [10], use rock specimens for impact damage experiments, and obtained impact damage characteristics and damage degree of the rock and the rate of the change of sound wave velocity; Han Fang et al [11], evaluated the degree of damage to the rock block through the ultrasonic testing to quantitatively; Li Xianglong et al [12], studied the relationship between damage of rock material and wave length and amplitude of stress wave by using the law of stress wave parameters on the damage and failure of rock material; Liang Tiancheng et al [13], measured the acoustic emission and ultrasonic wave velocity of rock during uniaxial compression damage, and compared the changes of acoustic emission and wave velocity with the damage process; Yuan Xiaoping et al [14], established meso-mechanical model of rock microcrack propagation, studied the meso-damage and plasticity of rock, and analyzed the damage and macroscopic plasticity of the model from confining pressure and short micro-crack length.…”