The invention relates to a method for evaluating the effect of demand response participating in peak clipping and valley filling of power network and is characterized in the following steps: 1 obtaining load and power grid side data before and after demand response implementation by adopting a power grid historical operation data investigation or simulation method, and collecting the data to obtain relevant data of daily load in any quarter and calculate energy status of equipment; 2, quantitatively evaluating the influence of the four demand responses of the percentage of the equipment energystate exceeding the limit time, the load reduction ratio in the peak period, the active power reduction ratio injected into the feeder in the peak period and the network loss reduction ratio in the peak period on the user side and the network side by participating in the evaluation index of the effect of peak clipping and valley filling; 3, evaluating the effect of the demand response participating in the peak clipping and valley filling of the power network by utilizing the evaluation index of the step 2. The invention is conducive to the optimization and selection of the demand response strategy, and has guiding value for evaluating the effect of the demand response participating in auxiliary services such as peak clipping and valley filling of the power network.