Abstract: For the problems that electronic evidence is easy to be tampered with and difficult to store, a blockchain electronic deposit and forensics system based on DPOS is proposed. Blockchain and smart contract technology were utilized to enhance the integrity, authenticity and non-repudiation of evidence and reduce human intervention. This paper optimized the consensus algorithm DPOS (Delegated Proof of Stake), so that it could reduce the weight of malicious nodes in time and weaken the tendency of their centralization. The storage pressure of the blockchain was reduced by means of on-chain and off-chain separate storage. For off-chain storage of data, a dynamic load balancing algorithm based on the state of the storage node was designed to improve storage efficiency. The experimental results show that the improved consensus algorithm can reduce the chance of malicious nodes participating in the consensus faster, and the degree of decentralization was improved. The optimized load balancing algorithm can respond faster and allocate more reasonably than the common load balancing algorithms.