In this paper,introduction is made to the proposal of upgrading from 160,000 t/a coal tar hydrogenation plant to inferior diesel hydrogenation plant.Bottlenecks possibly occurring in technique and in equipment during the modification are analyzed.The modification will have additional desulfurization system by circulating hydrogen,hydrogenation feed pump,H2S stripper and pump at bottom of diesel fractionating column,this upgraded plant will have capacity of refining 440,000 t inferior diesel per year.It’s reported in technical and economic evaluation that after the modification,the operating cost is totaled at ￥532 Yuan for refining per ton of diesel.

"> Coal tar, Upgrading, Inferior diesel, Hydrogenation