Visualized coverage model is usually applied for the evaluation of site planning and networks robustness in the spatial networks, which can help the users to understand and analyse the spatial data. In this work, a spatial network model of city-wide carparks service capabilities is studied in a visual dynamic coverage way. Firstly, the ParkingRank algorithm was used to model dynamic service capability of each parking lots in real time. Then, an improved weighted Voronoi diagram featuring boundary constraint was introduced to map the ranking value of each carpark to the geospatial space, forming a seamless and nonoverlap coverage over the city. Advantage of the proposed model is that, the coverage scope of each carpark can be adjusted dynamically according to its changing ranking value. By visualizing the parking lots network, it can provide great helps for the city-wide parking management.