Supported by the National Key Technology R & D Program-Police Geographic Information System Project (PGIS), Ministry of Public Secrity carried out PGIS platform study and promoted a demonstration project in Shanghai Public Secunty Bureau. Many formations of the Shanghai Public Security Bureau have both time and space attributes, and update with the rapid urban change. The common GIS technology not reflects the characteristics of the data very well. To this end, we build Police Geographic Information System base on Space-time Relationship (SPGIS).In this article we studied the six aspects of SPGIS, i.e. main features, temporal and spatial data processing method of data, architecture design, database design, GPS design, and display mode. SPGIS, based on geospatial data, adding the time dimension, to display and analysis data space attribute and time attribute, could promote people's understanding and analysis of police information. SPGIS is an open architecture system, ensures that all data can import to the system at any time through the temporal and spatial processing of data (data is processed into longitude, latitude, altitude, and time element as well). The system database also is divided into reality database, historical database, real-time database, GPS database, and so on. According to the results of this study, we completed the Shanghai Police Geographic Information System, and put into use in Expo 2010 Shanghai China. The system focuses on the open architecture system, the sustainable data update mechanism, time effectiveness of data, and data mining based on Space-time Relationship. Every type of data which include space and time attributes has been displyed,exchanged, shared and associated in a unified platform, and has been integrated to be managed, analysed and mined. During Expo 2010 Shanghai China,the system provided strong support in command and decision of police work, and in investigating of cases and events.