The invention provides an establishment method for a no-load model for an excitation system of an engine. The method comprises the following steps: establishing the no-load model for the excitation system of the engine in a digital-analog hybrid real-time simulation platform; connecting the no-load model of the excitation system of the engine with an actual excitation regulator and establishing a closed-loop simulation environment; establishing a no-load operation working condition of an engine group and testing no-load features and phase steps of the engine; and simulating accuracy of parameters in the no-load model for the excitation system of the engine. The establishment method for the no-load model for the excitation system of the engine has the following beneficial effects: the method is capable of effectively and accurately simulating a mixed simulation platform, establishing the no-load operation state of the engine group same with the spot; cost of manual power, material and money cost are effectively saved; meanwhile, a condition is provided for technology of a model establishing person on the training field for measurement; and stable operation of an electric system is ensured.