Abstract: How to focus distributed data and service resources efficiently for urban emergency decision support and rapid response is a vitally important issue that has to be addressed in the process of smart city construction. In this paper, an event-driven focusing service pattern for city information resources is proposed. It triggers the decision process by events, and realizes a seamless integration of requirements and city information resources, providing comprehensive auxiliary decision support in urban public emergencies. A registration information model for a decision information focusing service chain are also illustrated. Furthermore, an event-driven system for focusing distributed city information resources was designed and implemented. System application experiments were performed with a gas leakage event as a test case. Results show that the proposed focusing service pattern, registration information models, and system are feasible and suitable for emergency response.decision support in the smart city.