Existing decentralized access control solutions primarily cater to off-chain systems and adopt static policy evaluation mechanisms that fall short in addressing the unique requirements of on-chain environments. Challenges such as granularity, upgradability, and cost-efficiency in access control for on-chain systems remain unresolved. To address these challenges, we propose and formalize On-Chain Dynamic Policy Evaluation (OnDPE), a novel policy evaluation mechanism serving as an infrastructure for decentralized access control with flexible granularity and upgradability. Furthermore, we formulate an OnDPE-integrated Decentralized Access Control (OnDAC) framework tailored for decentralized applications on EVM-compatible blockchains.