In order to solve the drainage problem and minimize the total water drainage and storage cost in urban polder areas, an optimization model is developed with the present minimal total cost as the objective function, based on the construction concept of sponge city. In this model, constraints include pumping capacity according to the sponge city construction standards, the relationship between pumping capacity and main drainage parameters such as surface water ratio and sunken green space ratio in the polder area according to the design standards of drainage, and the urban ecological water demand. The decision variables are pumping capacity, surface water ratio, sunken green space ratio and permeable pavement ratio. This model is a non-linear mathematical model using penalty function method. It was then applied to the water drainage and storage project in Xincheng high-speed railway district, north Xinbei of Changzhou. The results of the drainage discharge, surface water ratio, sunken green space ratio and permeable pavement ratio were 61.28 m3/s, 11.97%, 51.77% and 15.00% respectively, optimal results were achieved. This model provides a new approach to the optimization of main design parameters of urban drainage in polder areas.