Abstract: The strong volatility and weak supportability of renewable energy, such as wind power and PV, have adverse effects on the power system stability. Therefore, the control strategy of multi-energy frequency division complementation is proposed to combine thermal, hydropower and energy storage to deal with high volatility of new energy grid-connection based on spectral density of wind power and PV output obtained by DFT. Firstly, the fluctuation power is decomposed into low, medium and high frequency components by two wavelet packet decompositions. Then, aiming at minimizing annual operating cost, the regulated capacity of different units is optimized according to the output characteristics of different energy units by introducing fluctuation penalty coefficient. The case study is carried out with the data of wind farms and PV stations located in the west of China, and the correctness and feasibility of the proposed optimization method are verified.