Abstract: With the continuous advancement and implementation of digital active power grid construction, the traditional functions of smart electricity meters can no longer meet the new requirements of multi-agent energy and transaction data in terms of interaction and privacy protection.This paper designs a smart IoT electricity meter extended function module based on blockchain technology, by combining modular architecture and blockchain technology, smart IoT electricity meter device information and data information are connected to the blockchain, and achieved data encryption and distributed storage, enhancing the credible mutual recognition among the participants in digital active power grid. This paper designs and builts a smart IoT electricity meter on-chain test system, tested to verify the compatibility and correctness of the expansion module based on blockchain technology.