Given the necessity for making incentive to behave optimally, as accepting new concepts and institutions are welcomed, it deserves revise classic institutions and when they do not meet new needs of society, they would be modified or substituted by other good institutions. The promise’s duty in enforcing promisor to perform his obligation in the case of breach and exceptional nature of termination of contract has been accepted in Iran’s law which does not have enough efficiency and it should be revised; because it prevent to induce promisee to optimally behave and to mitigate damage and sometimes places him in a deadlock that he cannot averse. Conversely, in German law, in the case of breaching contract by promisor, and after giving him a reasonable time by promisee, if the promisor does not perform his obligation, the plaintiff can terminate the contract or insist on performing contract. The reform of civil code of Iran in the manner that it would include accepting the termination of contract and specific performance together, could respond to society’ needs and meet individual’s legitimate and reasonable expectations.