MetaExpand, an abbreviation for Universal Metaverse Expansion Protocol (token name: UMM), is a generic metaverse expansion protocol. It serves as a foundational infrastructure for the metaverse ecosystem, significantly reducing the technological gap between public chains and metaverse applications. MetaExpand provides friendly, metaverse-oriented storage, communication, privacy, cross-chain capabilities, and foundational plugins and development standards, allowing developers to focus less on the technological differences of the underlying blockchain. Additionally, MetaExpand will offer paradigmatic applications for basic metaverse components, usable both as public plugins and as starting points for rapid development. MetaExpand aims to be compatible with other mainstream public chains and empower them, extending and accelerating their metaverse development capabilities.