The invention provides a method for evaluating the interaction capacity of flexible loads. The method includes the steps that firstly, evaluation types of the interaction capacity of the flexible loads are divided, wherein the evaluation types include the four dimensions of response characteristics, interaction effect, power grid safety and economy; secondly, corresponding specific characteristic indexes are established respectively for the evaluation types; thirdly, the value of each characteristic index is calculated, and the interaction capacity of the flexible loads is comprehensively evaluated. According to the method, the interaction capacity of the flexible loads is evaluated from the four dimensions of response characteristics, interaction effect, power grid safety and economy, the corresponding specific characteristic indexes are established respectively for the evaluation characteristics of the dimensions, comprehensive evaluation of the interaction capacity of the flexible loads is achieved, and bases for judging the influence of interaction on system performance, safety, economy and other aspects are provided according to the specific characteristic indexes.