Since the 1,000 kt/a ethylene plant at PetroChina Dushanzi Petrochemical Company was started up, frequent leakage has been found in the medium pressure condensate line in DS superheater. This paper uses chemical calculation to analyze the deviation of DS pressure, finds out that the fundamental reasons for the frequent leakage of medium pressure condensate line in DS superheater E-3014 were the gas-liquid two-phase flow and the large flow overload erosion, and puts forward some optimization suggestions and effective measures.