In order to meet the high requirements of existing IoT for security assurance and remote configuration management mechanisms, the key technologies and applications of embedded SIM cards in the IoT field are studied. We focus on the business operation mode and supervision direction under the embedded deployment mode, integrated with the embedded SIM card and the near-field communication function, to analyze different solutions for contract management. Then it focuses on the identity authentication function of embedded SIM card technology, the function of supporting the IoTs and the function of local services, and provides the implementation method of the corresponding functional modules. Finally, by establishing an EAPserver experimental environment, testing the system functions, and simply testing the key service processes, it is proved that the scheme is feasible, new and effective.