The contract is the law of the parties. A law that cannot be reversed in principle and the parties are not allowed to change its provisions unilaterally. It is only their joint will that can be the cause of change and evolution in the terms of the contract at the time of concluding the contract or during its execution, which is also the authority arising from the sovereignty of their will. Despite the acceptance of the principle of the necessity of contracts in all legal systems and the need to respect the terms of the agreement of the parties, the impact of social and economic events on the contract between the conclusion and execution of the contract is undeniable. In fact, the parties to the contract take into account the foreseeable circumstances and enter into the contract. This statement is considered and reasonable for normal circumstances, but the occurrence of events that make the execution of the contract impossible, according to the laws of different countries, including Iran, exempts the obligee from fulfilling the obligation. Contract adjustment is a method according to which the parties apply to the contract when the circumstances and conditions of the society change to prevent unusual losses, in other wor a fundamental change in the prevailing conditions that causes difficulty in The results show that the adjustment of the contract in the event of a fundamental change in the economic conditions of the contract is actually the expression of the terms of the agreement of the parties to maintain the economic balance of the contract, and therefore the adjustment is not different from the interpretation of the contract and the discovery of the terms of agreement in the changed conditions, rather than the scope of the arbitrators' jurisdiction. be outside