Aiming at the problem that packet sampling technique has lower flow feature extraction accuracy in high-speed network，a real-time network flow feature extraction system is implemented in NetFPGA. Making full use of NetFPGA high running speed and powerful parallel processing ability，the system can support gigabit data throughput. This real-time extraction system consists of two key elements，including address mapping module and flow table core processing module. The former uses pipeline technique to index flow record quickly through Bob Jenkins hash algorithm. The latter can update flow table rapidly by parallelizing query and match flow record. Online traffic test results show that the system can achieve real-time flow feature extraction in 1 Gbps Internet COTITIeCtI OTI.