The reappearance of Imam Mahdi has some signs, and religious leaders have their purposes for considering and explaining them. The realization of these signs depends on their matching with concrete outside examples. The first requirement of these signs is to apply the criteria to guide us to actual symptoms, and secondly in achieving its realization, two major challenges should be met. Firstly, there is always the possibility of other instances for the observed signs and secondly there is always the possibility of making a forged instance for showing off the signs. Therefore, we need to take measures in order to implement the matching process and follow on until we safely pass these difficulties. The above criteria are twofold: Firstly, the match must be with certainty, Secondly, the evidence must have all the features of the actual sign and thirdly, the implementation of such a matching process should not lead to an attempt to re-interpret the narratives, Fourthly, the matching process should be in general coordination of the criteria and frameworks of religion and implementation of the terms should not contradict let any religious principle to be violated, Fifthly, the implementation process of the signs with evidence and instances should avoid examples that are likely to be fake, and to be on the safe side, focus on the signs that cannot be faked. With respect to the five criteria above, we can reach the real examples of appearance signs that are not numerous and instances of fraud may not be found in them.