在城市化快速推进背景下，单一轨道交通体系已无法适应日益多元化的通勤需求，迫切需要构建符合中国国情的轨道交通协同发展新模式，推进城市群、都市圈轨道交通一体化建设，为区域协调发展提供有力支撑。本文从“四网融合”的情景分类、基础设施和运载装备、运输组织与经营管理、规划建设运营机制4个方面综述了我国轨道交通“四网融合”的发展现状，分析发现当前国内“四网融合”存在客流强度低、票务系统不兼容、运营成本高、新建市域专线面临规划协同不足、客流培育困难等问题，需创新运营模式并优化技术标准。研究提出轨道交通“四网融合”的发展目标、示范案例、重点任务，包括构建“穿城+放射+多支”线网布局，推动技术标准统一与智慧化服务，并建立协同机制。通过融合规划、技术、运营及政策，实现多层次轨道交通网络的互联互通。

As China's urbanization accelerates, single-mode rail transit systems are no longer sufficient to satisfy increasingly diverse commuting needs. There is a growing demand for an integrated, multi-level rail transit model tailored to China's specific context—one that supports metropolitan and regional development through better network coordination. The study reviews the current state of rail transit integration in China across four aspects: (1) integration scenarios, (2) infrastructure and rolling stock, (3) transport operations and management, (4) legal and policy support. Key challenges include low ridership on certain routes, fragmented ticketing systems, high operational costs, uncoordinated planning of suburban lines, and difficulties in building a stable passenger base. These issues call for new operational models and improved technical standards. In response, the study outlines a development strategy that includes clear goals, pilot examples, and key tasks. It recommends a "cross-city + radial + multi-branch" network layout, unification of technical standards, smart service platforms, and stronger coordination mechanisms. By aligning planning, technology, operations, and policy, the goal is to achieve seamless integration of multi-modal rail systems and support more balanced regional growth.