Because many large and mediumsized cities in the drainage system in the face of heavy rainfall is difficult to solve in a timely manner, there will be urban flooding, resulting in personnel, property safety and other losses. We propose to set up a new drainage system for light columns in parts of the city: excess rain water on the ground flows down the glass column to the ground, while exposing the glass columns of the underground space to create a place to rest and play. The underground space can be different column size, different column distance, in a day under different angles of sunlight to form a different relationship of light and shadow. To enhance the diversity of refracted light, we have added prisms in different light, different angle of exposure, this structure shows its vitality and expressiveness, become the city's new landscape. However, the jury will also appreciate more information, such as how the drainage system works and how light travels between glass pipes and air.