Blockchain, as the foundation for cryptocurrencies, has recently garnered significant attention. It serves as an immutable distributed ledger technology, which allows transactions to be carried out reliably in a decentralized environment. Blockchain-based applications are emerging, covering numerous fields, including financial services, reputation systems, the Internet of Things (IoT), and more. However, blockchain technology still faces several challenges, such as scalability, security, and other unresolved issues that need to be overcome. This article provides a comprehensive overview of blockchain technology and its applications. We commence with a summary of the development of blockchain, followed by an examination of the blockchain architecture and a systematic review of the research and application of blockchain technology in different fields from the perspectives of academic research and industry technology. Additionally, we briefly outline the technical challenges and recent developments. We also explore possible future trends in blockchain.