Abstract: During the pumps'startup and operation in Urumqi Initial Station of Western Pipeline, mechanical seal superheat failure caused by oil and gas fumes leakage has happened for several times. In view of this problem, by observing the phenomenon of mechanical seal failure, studying the air blockage mechanism, comparing and analyzing the phenomenon and reasons of mechanical seal failure caused by air blockage and impurity blockage, the main reason for mechanical seal superheat failure and oil and gas leakage is identified as air blockage. At the same time, approaches to the mechanical seal superheat failure are proposed, including fluid filling repeatedly to fully discharge air before starting the pump, and during running, slowly opening the valve to vent air immediately when the temperature at the mechanical seal cover and flushing/cooling circulation tube are in a rising range. It is considered that the relative experiences in preventing the mechanical seal's superheat can be taken as a foundation in avoiding this problem in pump stations.