The urban road flood protection capacity is related with a lot of elements such as human factors and natural environment as the lake. The lake can storage water temporarily and improves the urban road flood protection capacity. Based on Internet of Things technology, we establish an urban road drainage system sandbox with the near lake to simulate the relationship between the urban road flood protection capacity and the lake. The experiment simulates urban road drainage with the near lake in different rainfall level. Simulation results show that the near lake can obviously improve the urban road flood protection capacity in Heavy Rain and Rainstorm, and partly improve the urban road flood protection capacity heavy rainstorm and big heavy rainstorm. This can interchange for the urban road drainage system design to improve urban road flood protection capacity, promote the urban natural environment protection including the lake protection.