Aiming at the problem that Ethereum platporm has simple data management function and poor performance of low throughput and high latency, a trusted storage mechanism based on smart contract in Ethereum was proposed. Firstly, a framework of trusted storage based on smart contract was proposed for solving data management problem exposed in Ethereum. Secondly, the framework and implementation of the proposed mechanism were expounded from the aspects of centralized data processing, authenticated data distributed storage and dynamic forensics. Finally, the feasibility of the mechanism was proved by the system development based on smart contract. The experimental and analysis results show that compared with the traditional relational database storage, the proposed method increases processing credibility, storage credibility and access credibility; compared with blockchain storage, it enriches data management function, reduces the cost of block storage and improves the efficiency of storage.