Data aggregation is a key technology in smart grid communication, enabling efficient collection of essential data while optimizing energy usage. However, the large-scale deployment of smart meters raises significant privacy concerns, as it may expose users’ lifestyle habits. To address this issue, this paper proposes an efficient and privacy-preserving data aggregation(EPPDA) scheme for IoT-enabled smart grid, leveraging smart contracts. First, a four-layer blockchain-based architecture is introduced to facilitate secure data aggregation. At the collection layer, the Boneh-Goh-Nissim system is improved to better suit privacy protection scenarios in smart grids. At the platform layer, blockchain’s tamper-proof features are utilized for secure storage and efficient querying of aggregated data. Performance analysis indicates that the proposed EPPDA satisfies key privacy requirements of smart grid systems. Finally, experimental results show that the proposed EPPDA reduces computational and communication costs while improving overall system efficiency.