The invention discloses a windows packet capture (WinPcap) + gigabit Ethernet external radiation source radar data transmission method. Through system resource configuration, an 8-circular-array antenna receives a frequency-modulated signal, two field programmable gate arrays packs 8-frequency-point data, two internal memory buffer zones are arranged in a signal processor; two data channels are arranged between an antenna receiving machine and the signal processor, two network cards are arranged at a receiving end of each channel; four frequency points form a group to be transmitted in parallel through two network cables; and two data receiving threads at the receiving end correspond to the two network cards and receive data. The data is stored in a ping-pong mode. The problems that an external radiation source radar data transmission system based on a private data transmission plate is long in developing cycle, high in cost and bad in portability, and a large amount of data is hard to transmit in real time are solved, and the fact that external radiation source radar information is transmitted in real time is achieved. Developing cost is low, portability is strong, and data can be directly stored in an internal memory. The transmission method can be used for external radiation source radar data real-time transmission.