Abstract: The volatility and randomness of new energy power generation such as wind and solar will inevitably lead to fluctuations and unpredictability of grid-connected power. By reasonably configuring energy storage units in wind and solar power stations, short-term fluctuations in the power of wind and solar power stations can be smoothed and the power quality of grid-connected power can be improved. Based on the smoothing control principle of the grid-connected power of wind and solar power station system, the minimum power and capacity configuration schemes of the energy storage system are determined respectively according to the maximum smoothing time constant of the first-order filtering method. In this method, the power and capacity of the energy storage in the wind-solar storage station system can be reasonably configured, and the energy storage system can be utilized to the maximum extent to achieve smoothing effect.The simulation model of wind-solar storage power station is built in Matlab, and the feasibility of the method is finally verified.