Inland inundation has become a major latent safety problem faced by cities in China. As more emphasis from the local government was given to construction than planning，and over-ground infrastructure than underground supporting facilities，construction and maintenance of drainage systems in cities has been lagging behind. Meanwhile，the “hardening” of ground resulted from rapid urban expansion greatly undermines cities’ ability to handle rainstorms and floods. In the future，cities in China are likely to be constantly troubled by inland inundation. Therefore，it will be a prolonged and arduous task to prevent and control city floods.