In Iran's social security system, there is ambiguity regarding the legal nature of some executive bodies special funds,Considering that recognizing the legal nature of funds in the laws governing the fund, its supervision and structural reforms is effective, so that this ambiguity becomes a legal and executive challenge in some cases. The current article using the method Descriptive-analytical and based on library studies, it has investigated the legal nature of pension funds affiliated to Iran's executive bodies. This article findings indicate the ambiguity in the legal nature of pension funds, on the one hand, is due to the silence of laws and regulations, and on the other hand, to the multitude of laws and regulations related to pension funds and their different rules regarding the matter is related. According to the current situation, in order to resolve the ambiguity of the legal nature, the amendment of the statutes of special pension funds with an ambiguous legal nature by the Supreme Welfare and Social Security Council, which, based on Article 17 of the Law on the Structure of the Comprehensive Welfare and Social Security System, has the authority to amend the statutes of all It has pension funds, it is necessary. Also, in the meantime, issuing a unanimous decision by the Administrative Court of Justice in order to determine the legal nature (similarly to the determination of the legal nature of the Steel Pension Fund by the General Board of the Administrative Court of Justice) can be a way forward.