The invention provides a flight data knowledge acquisition system and an acquisition method thereof. The flight data knowledge acquisition system mainly comprises a flight data acquisition module, a flight database module, a mode selection module, a data preparation module, a data display module, a task execution module, a rule output module, a rule processing module, a knowledge acquisition module and a knowledge base module; and the system inputs and processes flight data, extracts useful data forming rules through rule acquisition operation, and supplies the useful data forming rules serving as knowledge to a user. The flight data knowledge acquisition method mainly comprises the following steps of: processing the input flight data, digging association rules by adopting an Apriori algorithm or a Mulit-Rule method, and supplying the extracted rules serving as knowledge to the user. The system and the method reduce the maintenance difficulty of a knowledge base by eliminating redundancy rules and merging the rules, implement an automatic knowledge acquisition process by using an association rule method, are suitable for processing multi-dimensional and single-dimensional data, and reduce manual input and dependency on expert experiences.