保險代位之本質，可說是整個保險代位體系之核心所在。本文乃以保險代位之本質—亦即求償模式為重心，對於保險代位之相關問題，依序加以討論。本文首先自保險代位存在之法理、以及學說上對其之批評加以分析、並提出回應。在保險代位之求償模式方面，我國傳統以來循大陸法系之傳統，採取法定債權移轉理論，而與英美法有所不同；英美法之架構近年來漸受學說之重視，甚至對其有所爭議，故實有釐清之必要。本文乃對英美保險代位之本質、架構加以探索，並對其與擬制信託之融合詳加分析，以求釐清其法律關係。除了英美以外，本文亦對其他主要國家之立法例詳加分析，並歸納為大陸法系與英美法系兩大系統。而中國大陸與台灣均屬於繼受法之地位，關於保險代位求償模式、名義等，亦可見受不同立法例所影響之軌跡；其許多條款與學說見解亦有疑義，值得我國引以為戒。於分析英美法與各國立法例，並審酌我國之背景後，本文乃嘗試對我國提出「保險代位求償模式相對論」—即原則上仍採取法定債權移轉理論，但在保險人與被保險人有特定具體之特約時，則可約定採取英美法之模式、或是自行約定其他求償模式。 另外，關於不足額保險、而應負責之第三人資力不足時，保險人與被保險人之間受償順序之問題，本文將由傳統的法釋義學方法出發，藉由對立法例、實務與學說見解的分析，以重新思考相關的法理基礎。本文也將使用法律經濟分析的方法，以經濟模型重新考量代位求償過程中可能的因素，重新驗證被保險人優先受償模式對於被保險人的效用。就結論而言，在損失填補原則的架構下，被保險人優先受償模式仍應為最適的解決方案。但此原則應有以法規或嚴格意定予以排除、修正之空間。在判斷順序上，可依三階段判斷：先檢視法規有無特別規定，再檢視當事人間是否有特別約定，若均無再適用被保險人優先受償模式以分配之。 對於特別保險—如全民健康保險法、勞工保險條例、強制汽車責任保險法等中之代位體系，本文亦加以分析，並同樣認為於適當之類型中，本文之保險代位模式求償相對論亦應可加以適用。在再保險與保險代位之適用問題上，本文肯認保險人對第三人之求償無庸扣除再保險之給付。而對於再保險是否、如何適用於保險代位，本文則認為可以三階段判斷之：首先，就再保險之類型為判斷；再判斷原保險人是否欲向第三人求償；如再保險之類型適合、又原保險人不欲向第三人求償時，則應允許再保險人向第三求償。最後，總結全文提出結論；並分三階段對於我國法提出相關建議，以供未來進一步之參酌。 / The nature of subrogation can be regarded as the core of the subrogation system. This research put stress on the nature of subrogation which was the subrogation. Regarding the related problems of subrogation, they will be discussed orderly. The article firstly starts to analyze from the existence of subrogation and the criticism for the theory to provide the responses. In the aspect of the way how subrogation operates, our country traditionally follows the Continental Law System to adopt the “legal assignment theory” which is different the Anglo-American Law System. The structure of Anglo-American Law System is stressed by the theory and is very controversial. Consequently, it is necessary to figure out the truth. This research is aimed at exploring the nature and structure of common law subrogation theory and analyzes other integration of the constructive trust to figure out the law relationship. Except for Anglo-American countries, this research also analyzes the lawmaking of other countries and induces the two main systems which are Continental Law System and Anglo-American Law System. Mainland China and Taiwan belong to the status of Succession Law. Regarding the subrogation and nominal, it can be seen that the orbit is affected by different ways of lawmaking. Understandings of many clauses and theories are still uncertain. Our country should learn a lesson from it. With analyzing the ways of lawmaking of common law and each country, and considering the background of our country, the research attempts to address the “relativity theory of insurance subrogation” to our country. In principle, it still adopts legal assignment theory. However, when the insurer and insured have specific agreement, they can negotiate to adopt the Anglo-American model or make other subrogation model by themselves. Other problems can arise with regard to payment priority between the insurer and the insured, particularly in cases of underinsurance and when the responsible third party has insufficient funds to make up the difference. The present study takes the traditional rechtsdogmatik approach as its starting point, analyzing legislative precedents, practical aspects and academic theories to re-examine the underlying legal principles. The paper also makes use of economic analysis of law techniques, employing economic models to reconsider the factors that may be involved in the subrogation process, and re-examining the efficacy of the insured-whole doctrine from the point of view of the insured. The main conclusions reached are that, within the framework created by the principle of indemnity, the insured-whole doctrine is still the optimal solution; however, there may be situations in which the insured-whole doctrine must be rejected or modified in light of legal or regulatory requirements or strict interpretation. Determination can be made in three stages. Firstly, the relevant laws and regulations should be examined to determine whether any special provisions apply. Then, an examination should be made to determine whether any special agreements exist between the parties concerned. If no special legal or regulatory provisions apply and no special agreements exist, then the insured-whole doctrine can be applied. For the subrogation systems in special insurances—for examples, the National Health Insurance, Labor Insurance, and Compulsory Automobile Liability Insurance, the research also analyzes them and considers that in the proper type, the relativity theory of insurance subrogation can be adopted. About the problems about reinsurance and subrogation, this research admits that insurer asks for subrogation for the third party not need to deduct from settlement of reinsurance. For reinsurer and how to apply to the subrogation, the research considers that it can be judged from three stages. If the type of reinsurance is suitable and the original insurer does not want to claim against the third party, it should be allowed that the reinsurer can claim against the third party directly. Finally, the research makes the conclusion and provides related suggestions to the law of our country to be viewed as the future reference.