Cellular mobile communication system divides the service area into several adjacent cells; each cell sets up a base station. In the traditional cellular representation, we always use regular hexagon to represent the cell. In the practical engineering applications and wireless network planning simulation systems, as the programming environment is complex and diverse, using the regular hexagon to represent the cellular network has limitation. This paper used Thiessen polygon and spatial analysis method to describe the cell service area with a polygon. This method intuitively displayed the relationship between the scope of service and its place with each other in space. For the Pre-construction and later optimization of wireless network planning it has a positive role.