Research conclusions: If the most substances in water and mud bursting are mud and sand, it is difficult for pumping water to treat water and mud bursting. In this case, the water stopping plug should be adopted to treat water and mud bursting. Based on the verification of the shearing force, the plug length should be designed according to the characters of water and mud bursting and grouting mechanism. The medium of the water and mud bursting in the Maluqing Tunnel is the cohesive soil and water, so the grouting mechanism should has the hustle-sediment action, the hydrate- concretion action and the float - sediment action in the cement concretion by the effect of the rainfall and the disconnected grouting. Therefore，the length of the water stopping plug must be of 10-20 times of the hole diameter.