Abstract: The introduction of digital and intelligent technologies has expanded the functional boundaries of libraries, while service process reengineering is becoming the core driver of their development in the GenAI era. At the new stage of transformation driven by digital technology, library service systems are undergoing a profound shift from mere technology adoption to process reengineering. From the four perspectives of systems, tasks, users, and services, this study analyzes the mechanism of service process reengineering oriented toward technological integration, the human-machine division of labor, human-AI relations, and context awareness. It further proposes a smart-library service architecture spanning five dimensions: infrastructure, data repositories, management information systems, platform operations, and physical space. The study further argues that deepening user-centered value creation within libraries, building an interlibrary collaborative ecosystem grounded in data interconnectivity, and constructing a smart service network for knowledge sharing are key directions for advancing smart-library service systems. Grounded in the practice of library digital-intelligent transformation and guided by a dual-drive approach based on demands and scenarios, this research both deepens understanding of service process reengineering and offers actionable strategies for the construction of smart-library service systems.