Leases are primarily concluded in the form of "mortgage or rent," in today common norm. Due to some legal objections govern on this type of contracts, jurists have raised suggestions including justification for the above contract in the form of conditions provided loans or conditions of loan and deposit on the rental contract. Among the solutions proposed in this regard, there is a method has been provided by some scholars such as Ayatollah Sistani and it will be remembered as a condition of sale and lease contracts. Meanwhile, the question that arises is about the legitimacy of this contract. What are the different forms of this type of contract? Can we attribute them to the accuracy of the transaction in all given forms? The authors also explain the various assumptions discussed in this study.