On May 12, 2020, the IMT-2020 (5G) Promotion Group Security work group released the “White Paper on 5G Smart City Security Requirements and Architecture”, which focuses on the security requirements, security reference architecture and security solution recommendations for 5G smart city, aiming to provide security guidelines and best practice references for vertical industries to develop 5G applications. The white paper was jointly prepared by China Mobile Communications Group Co., Ltd., Security Research Institute of China Academy of Information and Communications Technology, State Information Center, Huawei Technologies Co., Ltd., China Information and Communication Technology Group Co., Ltd., ZTE Corporation, Xingtang Communication Technology Co., Ltd., COMAC Shanghai Aircraft Manufacturing Co., Ltd., etc. The white paper points out that while injecting new momentum into the development of smart city, the application of 5G technology will also bring new security risks. In response to the security requirements of 5G smart city, the white paper proposes a security reference architecture for 5G smart city, which covers the terminal layer, edge computing layer, network layer, industry platform/technology middle platform layer, application layer and security operation management layer. With security implementation proposal provided for each layer, the white paper suggests that city managers and builders deploy corresponding security capabilities at each layer to ensure the safe operation of 5G smart city services.