The present invention relates to a method of preparing mono-iodo benzene with a transiodination reaction, and more preferably a method of preparing mono-iodo benzene including a step of performing transiodination of a reactant including benzene and at least a multi-iodo benzene selected from the group consisting of di-iodo benzene and tri-iodo benzene with an HY or HBeta type of zeolite having a Si/Al molar ratio of 10 to 100 as a catalyst. The method of the present invention has an advantage that iodine is recovered from by-products including m-di-iodo benzene, o-di-iodo benzene, and tri-iodo benzene obtained in the process of preparing p-di-iodo benzene, thereby resulting in minimizing the loss of iodine.