Today, in providing public services to the people, various types of contracts play a key role, and due to the growing need for this type of services and the lack of financial resources of governments (public sector), the importance of public-private partnership contracts doubles. The principles governing partnership agreements require comprehensive knowledge of the general and specific rules and regulations of such contracts, which should be considered by the parties to the contract. The type of partnership, the life of the partnership projects, the financing of these projects, the political, social and especially economic developments of the society and finally the laws governing this type of contracts are among the factors that may create a special form of partnership contract. Therefore, the legal implications of these types of contracts and the incentive to participate are very important. Adherence to the rules and regulations of participation in projects will minimize the differences between the participants in the project and respect the rights of the parties to the contract. Carefully in the laws and regulations of the country, one can understand some patterns of public-private partner-ship. The present study seeks to review, analyze and finally formulate the principles governing partnership agreements in accordance with the existing laws and regulations of the country in order to facilitate and encourage private sector participation. The main purpose of this study is to provide principles that, while governing this type of contract, can make the conclusion of this type of contract attractive both for the government and other executive bodies and for the participants.