Abstract: In order to study the flow laws of gas in coal body under the condition of negative pressure, a negative pressure controlled triaxial servo-controlled seepage equipment for fluid-solid coupling is introduced. Through installing negative pressure loading and control device, it also can be used to study permeability of coal containing methane under the comprehensive conditions of different temperature, loading negative pressure, crustal stress and gas pressure. During the experiment, the axial pressure, confining pressure, inlet gas pressure and the outlet pressure of the load is adjusted. The results showed that: with axial pressure increasing, coal is compressed in axial, radial expansion, and volume becomes smaller, and coal is compressed; the strength of coal increases with confining pressure; with the increase of negative pressure, the gas seepage velocity of tectonic coal sample gradually becomes larger, under the conditions of axial pressure, confining pressure and gas pressure is stable. Negative pressure is low (less than 15 kPa) with the increase of negative pressure. The gas seepage velocity increasing range is larger. When the negative pressure is high (more than 15 kPa), the gas seepage velocity increases more and more small, eventually even tends to 0.