Abstract: Unauthorized disposition contract is a valid contract, which has been widely accepted by academic cycle As an unauthorized disposition contract, contract of bona fide should also be valid There is unauthorized disposition contract done by one unauthorized person, and good faith cannot correct the defects of disposition deficiency, so the nature of bona fide should be taken as original acquisition, and the reason for bona fide assignee to obtain ownership is regulated by law Obligation cancellation of bona fide contract is not due to debtors′ repaying, but because unauthorized disposition cannot transfer ownership, and the obligation of transferring ownership has converted into compensation obligation Since the bona fide assignee has finally gained ownership according to the law, on the basis of the principle of compensation for damage to fill, compensation obligation of unauthorized disposition person is also destroyed, so obligation of bona fide contract is eliminated

Key words:  repay, elimination of debt, original acquisition, subsequent acquisition, unauthorized disposition contract