The Bitcoin system can be understood as a third-order computing system, where each order reflects a process of emergence from disorder to order, ultimately forming a trust based computing world. First Stage: Human Social Computing Input: Consensus of individual human values, culture, energy (electricity). Process: human society converts energy into electricity, drives computer networks and forms the Internet through culture and cognition. Output: The computer world provides infrastructure and energy for second-order computing. Emergence: From individual consensus to collective consensus, forming a social, cultural, and value system. Level 2: Internet distributed computing Input: computer computing power, network connection, Bitcoin protocol. Process: The miner nodes generate new blocks and nonce values through competitive computation (POW). Output: blockchain, timestamp, nonce (as the energy and time source for third-order computation). Emergence: From disorderly competition for computing power to orderly blockchain and timestamps, forming a trustworthy distributed ledger. Third order: UTXO trust computation Input: Nonce, UTXO (Unused Transaction Output). Process: UTXO based transaction verification and settlement. Output: A trust computing world based on nonce as the time reference and UTXO as the individual. Emergence: From disorderly transactions to orderly value transfer, forming a decentralized and secure value network. The connection between the three levels: Human society provides the energy and value foundation for the Bitcoin system. Internet distributed computing provides a secure and trusted environment for UTXO trust computing. UTXO trust computation ultimately presents the value and functionality of Bitcoin. Conclusion: The third-order computing system of Bitcoin embodies the essence of computation: transforming disordered information and energy into ordered structures and values. The emergence of each level drives the system towards higher levels of complexity and intelligence, ultimately forming a trust based computing world, which heralds a new direction for the future development of the computing world.