保險係藉由團體力量來分散個人危險、填補其損失的經濟制度，其目的並非使被保險人藉由保險給付而獲得超過損害額度的利益。另一方面，若被保險人得因保險給付而獲利，也可能間接提升道德危險發生的機會。從而，在得以認定被保險人因保險事故所受經濟損失額度的險種（損害保險）中，遂有所謂的「利得禁止原則」（Bereicherungsverbot，又稱為「不當得利禁止原則」）。本文所探討的主要問題為：利得禁止原則在我國保險法上是不是具有強制拘束力，並因而被保險人在保險法上的不當得利，是否同時構成民法第179條的不當得利？為完整解答此一問題，本文漸次檢討下列子題：（1）利得禁止原則規範拘束力是否存在？（2）基於利得禁止原則所設置的超額保險、複保險與保險代位等規定，是否屬於強行性的法律規定？（3）與上述規範相關，但法律卻未盡詳盡或周詳的問題上，是否應基於利得禁止原則的拘束力，而以類推適用或目的性限縮來處理相關爭議問題？（4）在上述規範以外的事項，是否亦應肯定利得禁止原則的規範上拘束力，以解釋或評價保險契約約定或保險給付的效力？本文主要研究結論為：利得禁止原則並不是一個當然具有規範上拘束力的法律原則，其規範上拘束力的發生及其效力範圍，有賴於制定法加以形成及確定。超額保險、複保險以及保險代位等規範，在防止被保險人獲得超過損害額的補償，且兼有抑制道德危險功能，應以絕對強行規定的性質理解之；違反該等規定而受領超過損害額補償者，應對保險人負不當得利之返還責任。至於其他非法律明定禁止超額受償的事項，但卻有產生超額補償的可能性者，不宜逕以違反利得禁止原則而否定其效力；此時被保險人縱使獲有保險法上的不當得利，亦不構成民法第179條的不當得利。

Insurance is an economic institution that transferred insured risk by pool and compensation for loss or injury. The aim of insurance doesn't encourage insured to get excess insurance amount from insured event. On the contrary, if we allow insured to get excess insurance amount from insured event, it might be raised the probability of moral hazard indirectly. Therefore, the principle of indemnity means that the insurance company in an amount exceeding the insured's economic loss may not compensate an insured. The questions are discussed as follows in this paper: Should the principle of indemnity be taken as mandatory rule in Taiwan? Also, is the principle of unjust enrichment in Insurance Act equal in Article 179 of Civil Code? To answer above the questions more deeply, this paper presents plural sub-questions below: (a) Does the principle of indemnity have legal binding? (b) The principle of indemnity including excess insurance, double insurance, and subrogation. However, are these regulations belonging to mandatory rule? (c) Should we take the rule of ejusdem generis or purposive approach to the principle of indemnity to solve them that are some issues and questions relating to above the regulations, but not regulated detailedly? (d) Apart from that situations except for (b) and (c) above should we accept the principle of indemnity as legal binding to resolve the question about agreed insurance payment by explanation. Consequently our conclusions are as follows: the principle of indemnity is not a legal binding principle. If the principle of indemnity has legal binding, it would be based on legislation. The regulation about excess insurance, double insurance, and subrogation shall be deemed as mandatory rule, because these regulations prevent insured to get payment beyond damage amount, and decrease occurrence of moral hazard. If insured violates above the regulations, insurer should be recovered excess amount from insured. As for another scenario in which insured get the possibility of payment beyond damage amount should not cancel or to stop it have any legal effect base on violating the principle of indemnity. In this situation, even insured gets unjust enrichment, insurer can't recover excess amount in Article 179 of Civil Code.