The invention discloses an elevator overhauling method and system based on internet of things. The elevator overhauling method comprises the steps that a mobile terminal sends request expected data toan elevator terminal through a cloud service terminal; the elevator terminal determines target system parameters and target operation parameters according to the request expected data; after the target system parameters are amended by the elevator terminal, target answering parameters used for representing whether amending is successful or not are generated; the elevator terminal uploads the target operation parameters and the target answering parameters at a set frequency to the cloud service terminal; the cloud service terminal saves the target operation parameters and the target answeringparameters according to the request expected data and then sends to the mobile terminal; and when work personnel arrives at an area with a plurality of elevators needing to be maintained, the mobile terminal is used for sending the expected request data, the elevator terminal receives the expected request data and then determines the target system parameters and the target operation parameters, the target answering parameters of the mobile terminal are returned to the mobile terminal, and thus the work personnel can obtain inner data of the elevator and change the system password of the elevator without the requirement of entering the elevator for overhauling.