In this project, the park will be set up under the ground. For lush greenery, sufficient sunlight and air are the most important and one of the great challenges of underground parks. Two ways of light flow. One is the sunlight through the double concave lens, which spreads the light in the space under the ground and increases the brightness through sunlight refraction and reflection. Another one is the application of amplifying lens and stack effect，concentrating light through a lenticular lens，achieving the effect of convection, keeping air circulation underground.