To address the bottlenecks and limitations in performance and security of existing coin mixing protocols on Ethereum， an improved coin mixing protocol based on verifiable shuffle， named EncMix， was developed. Firstly， a verifiable shuffle mechanism was incorporated to ensure that the fund flows of all participants remained completely untraceable. Next， ElGamal encryption combined with Chaum-Pedersen zero-knowledge proof was used to significantly strengthen anonymity. Finally， smart contract logic was optimized to eliminate unnecessary computational steps， thereby reducing the gas consumption required for the coin mixing process. Experimental results showed that， compared to the existing MixEth protocol， EncMix reduced costs by at least 200 000 gas per full coin mixing operation. Furthermore， under random oracle model， the EncMix protocol was proven to possess anonymity， availability， and theft-proof characteristics. In conclusion， EncMix enhances performance and reduces costs while ensuring the security of blockchain transactions， providing more robust technical support for decentralized finance applications and generating considerable economic value.