With the rapid development of urbanization level, the continuous expansion of urban areas and unreasonable planning have taken place in the underlying surface of the city. River and lake water systems, wetlands and green land have been occupied, and the impervious area has increased, which has destroyed the hydrological cycle of the city, leading to a series of urban water problems. The construction of a sponge city is an important measure for similar problems. Aquatic plants are the most important part of water ecological restoration technology. Their developed roots can absorb nutrients in the water. Moreover, using aquatic plants as the main body of water for ecological restoration can not only control the eutrophication of water, but also have a good landscape effect, and will not cause secondary pollution. Therefore, the purpose of this paper is to explore the problem of improving the sponge city environment by aquatic plants based on ecological restoration theory and analyze the problems and solutions in the process of sponge city environmental protection construction. In this paper, the research method of specific analysis was used to compare the data to achieve a conclusion. The results showed that the development mode of sponge construction in practical cities will effectively reduce surface runoff by 15% and rainfall and flood by 21%. It can also solve the problems of urban waterlogging, water ecosystem restoration and heat island effect mitigation. Therefore, it was of great significance to study the ecological mode of rainwater utilization in the construction of a sponge city, analyze the collection ways and different application modes, to relieve the pressure of urban water resources and promote the efficient and comprehensive utilization of water resources in China.