Abstract: Unloading method of injecting nitrogen to tank car to raise pressure and liquid extraction with centrifugal pump simultaneously is often used to unload butadiene tank car. The method presents many problems such as large amount of nitrogen consumption, high cost, environmental pollution, etc. By comparison to four kinds of unloading methods, the method of using hot water exchanger to heat butadiene to make it gasifying is applicable. Butadiene autopolymer generating problem is controlled effectively in such aspects as adding flocculation stopping agent, removing activated agent, reducing oxygen content and controlling temperature. Consequently, get good economic and social benefit.