Public opinions and popular feelings are embodied in public urban data，which is a direct record of society operation and a direct reflection of social laws. In the era of big data as resources，numerous public data is undoubtedly a valuable resource for the whole society. However，the public urban data is in a large scale and in large varieties，it has become a hot issue for all walks of life in society to manage and use the public data better，to improve the level of government services，and to launch the brand of government services，it is also the work focus for Shanghai Big Data Center. It is important to improve government services efficiency and meet the needs of the public with the use of big data，including ensuring data security，exploring the public opinions in big data，optimizing government processes with big data and the internet to serve enterprises and the public faster and better. Based on the current status of centralized management and sharing of public urban data provided by Shanghai Big Data Center，this paper redevelops the concepts of Data Lake on municipal level and Subject Database under the new background of building smart city and smart government. It explores the needs of management and utilization of public data，and then combine them organically. Thus it proposes to further deepen the reforms to streamline administration，delegate powers and improve regulation and services，aiming to build a new public urban data management and sharing structure，based on the Public Urban Data Lake，supported by municipal database named “Four Beams and Eight Columns”，applying the “Three Lists and One Catalog” as the supply and demand management mode and taking the application scenario authorization as the main sharing mode. Up to now，the total design capacity of Data Lake in Shanghai Big Data Center is 5，400TB. 4.68PB of data has been collected and 8.77 billion pieces of data have been extracted. 7.998 billion effective data has been put into the Lake，including 5，120GB data of population database and 91，020GB data of electronic license database. This structure solved the technical problems of managing public data for the governors in the city and provided the management and sharing methods of urban public data，realizing the promotion from management to service.