A model updating method and apparatus, and a system, to resolve a problem of network performance deterioration due to model performance deterioration are described. A first function entity sends a model update policy to a second function entity. The model update policy includes an update condition of a model of a first network element, and the model of the first network element indicates to adjust a parameter of the first network element. When receiving an update request, the first function entity performs a procedure of updating the model of the first network element, where the update request is triggered by the second function entity in accordance with determining, by the second function entity, the model meets the update condition.