As the value of decentralized finance (DeFi) continues to increase, it has become an increasingly sought-after area within blockchain technology. However, the accompanying Maximum-Extractable Value (MEV) issue has begun to raise concerns. MEV is closely related to transaction ordering, which makes sequencers with ordering power the primary target for participants seeking to manipulate transaction ordering for profit. This undermines market fairness and causes losses for other users. To address this issue, this paper introduces MEVShield-an anti-sequencer manipulation framework that uses a secret election mechanism to protect sequencers from malicious threats. MEVShield employs a secret election mechanism to keep sequencer identities confidential, ensuring the security of sequencers and the fairness of transaction sequencing. We conducted a comprehensive security analysis and implemented MEVShield to evaluate its performance. The experimental results demonstrate that the proposed scheme achieves a high level of security while maintaining acceptable computational and communication costs.