In the Civil Procedure Law, the legislator has provided for a temporary order to protect the rights of the petitioner, and by mentioning Article 321 of the said law, he has also secured the rights of the respondent. But mentioning the word expediency has created the possibility of different interpretations. In order to analyze the concept of expediency in the subject of Article 321 of the Civil Procedure Law, this research, which was developed in a descriptive-analytical way, first stated the criteria for determining expediency and then reached the results that, unlike Western legal schools, Iranian law, based on the conceptual rule of expediency, considers spiritual needs in addition to material needs. Secondly, although it is better to refer to the common sense in the assessment of expediency, it is concluded from the examination of the criteria for determining expediency that only in the case of Article 321 of the Code of Civil Procedure, it is appropriate that the determination of expediency based on the rule of gratitude is in the hands of the judge so that he can issue a more correct opinion according to the general criteria of expediency and of course taking into account the circumstances of individuals. Therefore, it is clear that in this topic, the scope of expediency is to observe the interest of the person against whom the temporary order has been issued, not regardless of it. Therefore, it is obvious that judges will get confused in practice if expediency assessment is delegated to the legislator and they will face problems in the stage of adapting expediency to the conditions of various people.