Abstract: The operation experience of adjusting end-point of delayed coking gasoline of 1.5Mt/a delayed coking unit in Karamay Petrochemical Corp is summarized. The issues during the adjustment are discussed in terms of diesel system overloading, top circulating reflux pump exhausting and salt deposition on column trays. It is proved that the above issues could be handled appropriately by optimizing diesel process flowsheet, adding top circulating water sump，and cleaning tray periodically. As a result, the coking gasoline end point could be controlled under 180 ℃ and used as the feed for reforming. The diesel yield increases by 3.45% as well as higher diesel to gasoline ratio.