The invention relates to a prediction-based service degradation method in a power data communication network. The method comprises the steps of obtaining history data; carrying out service prediction and service priority division based on the history data, and obtaining related data of service requests in a control period according to an improved interpolation prediction method; and sorting the service before the current service request according to a priority sequence, wherein the priority of the service is lower than a current service quest type, and carrying out calculation resource degradation on all service requests which can receive resource degradation and have the lowest priority type. For the improved interpolation prediction method of the service quests, the prediction precision is improved, and relatively basis is provided for network planning. In the network optimization aspect, when a network is overload, the calculation resource degradation and bandwidth degradation are carried out on the service requests to which the resources are allocated, in a user acceptable range, partial resources can be released to new service requests, and a service congestion rate is reduced.