To solve the datalink problem of capability and service/price, a frame work model——a new datalink user's redundant strategy was proposed, based on reliability theory. The redundant strategy could be combined with the normal maintenance, which greatly improved the performance of the network system. The static-checking and policy of authentication mechanism ensured the running network without any error. The redundant equipments were independent but were capable of communication with each other when they work their actions. The model was independent of specific application environment, providing a general-purpose framework for fault diagnosis. An example was given to express the calculating method.