SixDomainChain (SDChain) is the world's first decentralized public blockchain ecosystem that integrates international standards of IoT Six-Domain Model and reference architecture standards for distributed blockchain. Fully considering the technical characteristics of IoT and the development needs of business ecosystem, SDChain is optimized based on existing blockchain technology with digital asset issuance, user credit and identity management, P2P communication, encryption algorithm, consensus algorithm, smart contract, cross-chain contract mode, market consensus-based incentives, decentralized DApp and rapid access to business. Such features ensure beneficial, rapid and sustainable development of SDChain business ecosystem to achieve mutual benefits among digital assets, blockchain and industrial IoT through efficient circulation and value transformation of digital asset credits, within a global framework of ISO/IEC standards.