Abstract: The main drive system of the shaft full face boring machine may face the impact of high pressure mud load caused by sudden water gushing, which puts forward strict requirements on the reliability of the system seal. In this paper, a new main drive sealing method based on active pressure compensation is proposed, zero leakage sealing evaluation criteria is proposed in combination with percolation theory and GW contact model, and micro and macro scale sealing structure models are established. Experimental studies on sealing characteristics under different compensatory pressures and external loads are carried out to reveal the evolution mechanism of sealing performance under the combined action of external cavity pressure and compensatory pressure. The results show that in order to achieve zero-leakage sealing, it needs effective contact between contact surfaces, and the sealing effect begins to occur after the contact stress breaks through the percolation threshold, and the subsequent increase in sealing capacity gradually tends to be synchronized with the increase in contact stress. Under higher confining pressure, the new main drive seal structure shows better sealing ability, and the maximum sealing pressure reaches 1.95MPa when the compensation pressure is 7MPa. At the same time, the analysis shows that the sliding of the contact surface and the sinking of the matrix have significant effects on the sealing effect. In practice, the pressure compensation in advance can effectively improve the sealing performance.