Abstract: The mass balance of diesel fractions produced in the refinery was calculated, based on the analysis of compositions and properties of hydrotreating feedstocks, product quality and calibration results of diesel hydrotreating unit in Xi’an Petrochemical Company of Sinopec in order to fine out the ways to upgrading the quality of the diesel pool of the refinery. A series of feasible revamping measures to upgrade the quality of diesel pool had been adopted to meet the requirements of National Emission Standard Ⅲ, such as replacing hydrodesulfurization catalyst, using new type effective feedstock filter, adding water heat exchanger before air cooler, optimizing operation conditions and feed compositions and lubricity modifier adding in diesel pool. Thus good economic benefit is achieved at low cost.