In order to realize the optimal design of rock-socketed pile foundation in mountainous area and effectively prevent the rupture of the rock, the compression mechanical behaviors and failure mechanisms of brittle rocks with different lithologies were experimentally and numerically investigated. Firstly, uniaxial compression tests were carried out on five kinds of brittle rocks based on the self-made compression testing system. Acoustic emission (AE) monitor system and digital image correlation (DIC) technology were used to discuss the characteristic parameters of AE signals during the crushing. Moreover, the characteristics of critical failure precursors and the evolution rules of damage failure of different rocks were obtained by using the nonlinear explicit finite element (FE) method. The experimental results were in good agreement with the corresponding FE ones. The results show that there are the obvious AE phenomena in brittle rocks during the uniaxial compression test, and the active degree of ringing count and accumulated energy can describe the internal damage of the specimens effectively. At the initial stage of the compression, there is no obvious crack on the rock surface. However, more cracks appear on the surface of the specimens with the increase of the compressive stress. The specimens are destroyed instantaneously when the compressive stress reaches the peak stress, and no new cracks are generated. The distribution and evolution of local strains can intuitively predict the breeding and expansion of new fissures. The research results provide theoretical reference for monitoring and warning of rock failure and foundation design of transmission line in mountainous area.