Smart City is a new concept that uses information and communication technology (ICT) to promote the smartification of urban construction, planning and services. Currently, a number of cities have conducted studies on smart cities, but they have mostly focused on analyzing the conceptual connotations or applications in specific domains and lack a shareable and integrated framework, which has led to significant barriers for individual smart projects. By analyzing the framework and applications of Smart City, this paper proposes a common, shareable and integrated conceptual framework. Then, based on this framework, it further proposes a unified portal platform that can balance multiple stakeholders, including the government, citizens and businesses, as well as for common, custom and other application modes. Finally, the implementation of Smart Weifang based on this platform is discussed. The applications indicate that this shareable platform can effectively eliminate the data and technological barriers between different smart city systems while also avoiding redundant financial investments. The investigation of this proposed framework and platform is highly significant for the unified construction of smart cities and the intensification of the hardware environment, thus representing a true achievement in the transition from 'information islands' to 'information sharing and interconnection' for urban informatization.Sustainability 2019, 11, 4346 2 of 16 and services by using ICT, such as the Internet of things (IoT), cloud computing and geospatial information [9][10][11][12]. Based on research on the smart city conceptual framework and characteristics, practical studies on smart cities have been conducted, such as the smart e-government "I-Japan Strategy" in Japan, the intelligent transportation study in Sweden, the smart grid projects in the US, and the smart community in Germany.However, despite the large amount of research conducted by numerous countries and cities on the smart city and the substantial progress that they represent, they mostly focused on the analysis of the conceptual framework and applications in specific domains (e.g., smart transportation) and lack a common, shareable and integrated framework of understanding. A city is a giant complex system. To meet the ever-changing needs of its citizens, all systems within the city should communicate accurately with each other and share and utilize each other's resources in a timely and rapid manner [13]. Smart projects in specific domains usually have the characteristics of a resource monopoly and mutual independence, which leads to the following issues: (1) The inability to guarantee the consistency of public data and the spatial base for different smart projects in the same city; (2) the inability to achieve the sharing and integration of different smart systems or data in smart cities; (3) the inability to guarantee consistency across different smart project implementations due to different viewpoints of the project implementers or researchers; and (4) ...