Traditionally, vector data management in geographic information system (GIS) applications often relies on general purposed database systems. However, the strict ACID semantics kept by database systems are not always necessary for most GIS applications to handle data in read-only mode. With the increasing quantity of vector data, the semantics mismatch has been becoming a critical challenge in keeping efficiency of GIS data management. In this paper, we propose VDMS, a Vector Data Management System, which managing data directly based on file systems. We first provide an improved mechanism to store vector data as standard shapefiles in individual regions. And we present specific APIs for spatial and non-spatial queries. Our experiment results demonstrate that VDMS can benefit the importing and query operations of vector data significantly compared to PostgreSQL.