Abstract: The operation of diesel hydrogenation unit expansion revamping for hydroprocessing the mixed feed of coker gasoline (naphtha) and non-aromatic naphtha were introduced. Problems during the operation and measures were discussed and proposed. The practices indicate that at the conditions of high separator pressure 3.40 MPa, reaction temperature of R1/R2 222℃/266~170℃，LHSV1.85 h-1，the sulfur content in the refined naphtha is less than 200 ?g/g, meeting the requirements for ethylene production and large load production as well. All transformation reaction, fractionation and desulfurization system can keep running smoothly. Some of the issues affecting the smooth operation of the device and product quality, after eliminating defects and operational adjustment, are basically resolved.