Mobile security robots use an environment map of its workspace to complete the surveillance task. However previous map formats such as grid map that uses a large size of memory for accurate representation of environment are not suitable for mobile robots. In this paper, we present the hybrid map structure that combined the advantages of the grid and topological maps. The prosed a hybrid map uses less memory than grid map and has same efficiency of a topological map. Mobile security robots use the hybrid for complete path planning and shortest path planning. Experimental results show that the hybrid map uses only 5% of the memory that a grid map requires. And results show a complete path planning.