The invention discloses a basic geographic data synchronizing method based on a PGIS (police geographic information system). The method comprises a plurality of police service systems and a data center, wherein each police service system comprises at least one data source. The method comprises the following steps of (1) registering the police service systems in the data center, storing the location and path information of the data sources of the police service systems in the data center, and establishing the data connection between the data sources and the data center, so as to realize the real-time accessing of the data center to the data sources; (2) establishing a lock synchronizing server, executing the uniform clock synchronizing algorithm on the data sources and the data center, and increasing a time stamp from the clock synchronizing server into the data of the data sources; (3) adding the position information of the data sources into the collected data, and converting the collected data of the data sources into the data with position information; (4) synchronizing the data of the data sources into the data center.