For a hydrogen network with purification, different purification feed purities (PFPs) and purified product purities (PPPs) will exert different effects on utility consumption. To optimize a hydrogen network with purification reuse, the effect of PFP and PPP on the hydrogen utility consumption should be analyzed systematically. According to the quantitative relationship of the hydrogen surplus at each sink-tie-line, the limiting PFP and PPP can be identified from the hydrogen surplus variation diagram. For sink-tie-lines at different regions, the quantitative relationships between the HUS and the PFP/PPP are analyzed. With the quantitative relationship line between the HUS and the PFP/PPP of each sink-tie-line plotted, the quantitative relationship diagram can be obtained. Based on this, the pinch point and the HUS for a given PFP/PPP can be identified. Furthermore, the limiting PFP and PPP, the optimal PFP and PPP, and the maximum HUS can also be targeted easily. A case is studied to illustrate the applicability of the proposed method.