Abstract: Grid and geocodes are dual. Grid is the dimension that geocodes represent, and geocodes are geographic identifiers of grid cell. Starting off with the definition of the grid, This paper discussed the characteristics of regulate and irregulate grid, focused on composition of multi-scale irregular grid, and pointed out that cadastry is a basic cell of urban flat surface and can make up other professional grid so that spatial information can be synthesized and shared. At length, this paper anlalysed and probed into the standard of geocodes based on irregular grids.