Abstract: The reversion seal sampling processes was simulated in the laboratory by using self-designed gas adsorption and desorption experiment device. The gas desorption experiments were done under different adsorption equilibrium pressure and seal time. Considering the process of adsorption equilibrium, discharging pressure and seal, the gas pressure of coal sample tank were analyzed. The experimental results showed that the gas pressure of discharging pressure process increase gradually and it was a process from nonequilibrium state to equilibrium state. Theoretically, as time went on, conditions may finally be equilibrium state. The gas desorption of coal by seal sampling is a nonequilibrium state desorption process, and the initial desorption gas is pronouncedly larger than conventional desorption gas. The desorption gas increases as adsorption equilibrium pressure and seal time increases, and its adsorption law is very similar to that of conventional desorption.