Abstract: To improve the efficiency of data query and rendering speed of navigation map display, it is necessary to organize the display objects of map into structures. A dual level grid structure of fixed rendering scope for multi\|scale map database was proposed, and based on this structure we designed a forecast loading strategy to improve the efficiency in directional moving navigation, and thus the average data loading time can be reduced. In the grid interior processing, a vision retrench rule was presented based on ocular distinguish characteristic. Using this rule, we retrenched the display objects inside the grids by appending, simplification, and merging, and thus we reduced the data amount in the grids and improved the rendering efficiency with map vision effect still maintained.