The invention discloses a modulation method for stable control over an air-conditioner group response power grid based on a probability model. The method comprises the following steps that the state of an air-conditioner before an accident occurs is recorded, and setting of the upper limit and the lower limit of the temperature, the compressor opening and closing state and the indoor temperature are included; after the accident occurs, the controlled air-conditioner load is cut off; after power supply is restored, the operation state of a controllable air-conditioner group is controlled, an air-conditioner closed at the initial moment of cutting off the load is started, the upper limit and the lower limit of the temperature are adjusted, and thus distribution of the air-conditioner load after being controlled is unchanged in the temperature dead area; and the change of power of the air-conditioner group along with time is solved by using the probability model, and an expectation valueof the change of the power of the air-conditioner group is obtained. According to the method, after the accident, the load of a whole feeder line is not cut off any longer, instead, the controllable load is cut off selectively, while the requirement of a power system is met, the great influence on users is avoided, when the load is restored, secondary impact on the system is avoided, normal operation of the power system after the power supply is restored can be guaranteed, and severe accidents occurring to the power system later are avoided.