The embodiments of the present disclosure provide a method and an Internet of Things (IoT) system for determining a gas meter measurement failure of a smart gas, the method including: by the smart gas data center, obtaining, based on the smart gas sensing network platform, gas flow information of pipelines of each level from at least one flow monitoring device, the at least one flow monitoring device being configured in the smart gas object platform; by the indoor smart gas device management sub-platform, determining a candidate area based on the gas flow information; determining a target gas meter based on gas meter reading information of the candidate area, and then determining a maintenance plan for the target gas meter; and sending the maintenance plan to the smart gas data center, and sending the maintenance plan to the smart gas user platform based on the smart gas service platform.