Ethereum, as the world's second-largest cryptocurrency platform, has always been the focus of attention for developers and users regarding its security and stability. In recent years, Ethereum has been continuously advancing its security program to address increasingly complex cyber attacks and potential risks. For example, Ethereum is gradually transitioning from a Proof of Work (PoW) mechanism to a Proof of Stake (PoS) mechanism. This shift not only enhances the scalability of the network but also significantly strengthens the security of the system and reduces energy consumption. Additionally, Ethereum is also strengthening the auditing and vulnerability remediation mechanisms for smart contracts by introducing more advanced code review tools and incentives to encourage developers to identify and fix potential vulnerabilities. At the same time, the Ethereum community is actively promoting security education to raise users' awareness of common threats such as phishing and malware. Nevertheless, security challenges for Ethereum still exist, such as the complexity of decentralized finance (DeFi) and the uncertainties of emerging technologies. In the future, Ethereum's security program will need to continue innovating and adapting to ensure its leading position in the ever-evolving blockchain ecosystem, providing users with a safer and more reliable decentralized application (DApp) environment.