This article starts from the theory of unjust enrichment categories, explaining that based on the theory’s basic normative concept—the state of property attribution should be adjusted according to regulatory characteristics and purposes of each legal field through unjust enrichment regulations—the scope of unjust enrichment of patent infringement should be determined in two stages, namely“unjust”and“enrichment”. In the first stage, it should be confirmed that the vesting of the patent right and the implementation of the patented technology by the non-patent holder violate the predetermined content of the attribution of rights by the legal order, constitute“unjust”gains, and cause damage to the patentee. In the second stage, the scope of the“benefits”received by the infringer should be explored. If the said scope is only limited to reasonable royalties at this stage, it may not only be confused with the relationship between the means and the purpose of the patent and the exercise of the rights but also with the reasonable royalties of the lost benefits of the damages. Furthermore, it is more likely that the patent right, originally an almost absolute exclusive right, will be downgraded or drafted into a right to claim compensation for similar compulsory licensing, thus eliminating the normative principle of infringement of rights and interests. However, when the court restricts the scope of unjust enrichment to reasonable royalties based on practical requirements, the calculation of the reasonable royalties should be done by using the“hypothetical negotiation method”faithfully. Finally, this article uses the specific facts of the Supreme Court’s civil judgment to illustrate how the above propositions can be applied to specific cases in order to reach an appropriate result.