The invention relates to the technical field of financial data monitoring. The invention aims to provide a method and system for realizing the transaction risk control by means of the network packet capture data, which can timely detect the risk of a business system, process the risk immediately, realize the real-time control of the business transaction risk, facilitate the rule increasing and adjustment, and can rapidly respond to the position risk behavior, and moreover, the existing business system is not needed to be reconstructed, and the data is integral and real in process. The method for realizing the transaction risk control by means of the network packet capture data realizes the effective risk control of the business by mirroring the flow data from the business system in real time. The system at least includes a data engine module, a data filtering module, a channel distribution module, a risk control module, a batch processing module, a risk alarm module, and a visual query module.