Abstract: As a by-product of oil refining and petrochemical production process, C₄ hydrocarbon productions increase year by year. It is estimated that the total annual C₄ hydrocarbon productions of refineries in China are more than 6 million tons, therefore the research of C₄ component separation and utilization of deep processing has important strategic significance and practical effect on the development of China's ethylene industry and related industries. At present, there are some difficulties on the extractive distillation of C₄ hydrocarbon separation and deep processing such as tray pressure drop larger, processing capacity not up to the full load, separation index of unqualified, high energy consumption. In this paper, the problems of C₄ hydrocarbon extraction towers and stripping towers before the renovation in Ningbo Haode Chemical Corporation are introduced. In view of the existing problems, the original DJ valve trays are replaced by the complete countercurrent trays. After the reconstruction, the processing capacity increases from about 80% loading to 130% loading, the steam consumption is saved by 35%, all indicators of productions are better, the phenomenon of liquid blocking device don't appear, and all devices are running smoothly.