The butadiene plant in the old area of PetroChina Dushanzi Petrochemical Company has been in operation since August 1995. It was forced to shut down due to polymerization problem after only less than half a year of operation, and it was shut down four times in 1997. Long cycle operation of the plant has been a difficult problem to solve. After technical research and transformation, the operation cycle of the plant was gradually extended to one year and finally reached four years. In this paper, the factors affecting the long cycle operation of butadiene plant are analyzed, and the best methods for extending the operation cycle are investigated, so as to increase the load of the plant and ensure the safe and stable operation of the plant.