The invention provides a flexible simulation method and system. The method comprises the steps of acquiring the initial power of an interactive load from a power grid simulation system; obtaining a power plan value of a flexible sub load according to the initial power and a pre-established flexible load model; performing simulation on the basis of the power plan value and the simulation type of the flexible sub load to obtain the output power of the flexible sub load; and performing correction on the equivalent load corresponding to the flexible sub load based on the output power of the flexible sub load, and carrying out power flow and frequency calculation according to the corrected equivalent load, wherein the simulation type comprises a plan tracking type and a self-defined simulationmodel. According to the method and the system, the limitation of a traditional power grid simulation system in the aspect of load side simulation is broken through; the flexible load model establishedin advance is adopted; simulation on the response characteristic of the flexible load and interaction with the power grid simulation are preformed; the power grid power flow and the frequency are calculated; and the influence of the flexible load on the operation of the power grid is effectively evaluated.