This experiment takes the coal samples from coal seam K3 in Songzao Tonghua mine of Chongqing as an object. Triaxial compression tests under different confining pressures and gas pressures are conducted with a self-developed seepage device. In addition, the experiment studies the characteristics of energy dissipation and seepage of the coal samples during compression process with the method of energy accumulation and dissipation. The results show that the coal samples containing gas have the process of energy accumulation and dissipation during the failure of triaxial compression test. And the energy is absorbed and stored in the form of elastic strain energy within the coal samples. When the load reaches the peak, elastic strain energy stored in coal samples releases instantly into the dissipation energy, which becomes the driving force of coal sample damaging. There is a great influence of confining pressure and gas pressure on the dissipation characteristic of the coal. With the increasing of confining pressure, the total energy, the stored elastic strain energy and the dissipation energy of the coal sample would increase. With the increasing of gas pressure, the total energy and dissipation energy of the coal sample would slowly increase, while the stored elastic strain energy would gradually decrease. Confining pressure and gas pressure also have a great influence on the permeability of coal samples. Before the peak stress, the permeability of coal samples would decrease gradually with the increasing of confining pressure and would increases with the increasing of gas pressure. The study results can provide some references for prevention of coal and gas outburst as well as extraction of coal seam gas.