The nature of division was discussed in jurisprudence and law books, but less was said about the nature of partition. Most of the writers in the study of division have also dealt with its nature and because they consider separation as one of the partitions of division, they have found themselves without the need to express the nature of partition. Recognizing the nature of partition; depending on whether the transaction (sale, exchange, interchange), or discrimination of the right or contract, the effects are different. So, is there a right of pre-emption and options in partition or not? Is it possible to rescind bilaterally (rescission, cancellation of a contract by mutual consent) in partition or not? Will the partition have an effect on the necessity or non-necessity of registering the division letter? The answer to these cases is to identify the nature of partition. In this article, analytically-descriptively, by studying the opinions of jurists (lawyers) and Imami jurists, we will say that the nature of partition into the theory of being a contract in the statute is somewhat more popular among jurists. However, being a contract does not necessarily mean transaction and sale, and there are no special rules of sale, including the right of pre-emption and the options specific to the sale. Naturally, due to the same contractual nature of partition, the possibility of rescission (rescind bilaterally, cancellation of a contract by mutual consent) and applying other options can be imagined and realized in separation.