The invention discloses a broadband channelization reception system of radar with an external radiation source and an FPGA (Field Programmable Gate Array) implementation method. The FPGA implementation method comprises the steps of: dividing received radar broadband signals into multiple paths of analogue signals through a power division filter module; transmitting each path of analogue signals after AD (Analogue-Digital) conversion into an FPGA for frequency point separation; converting to a baseband through down-conversation in the FPGA; sequentially carrying out a multi-phase structured deceleration treatment, channelization treatment, FIFO (First In First Out) series and parallel conversion treatment and FFT (Fast Fourier Transformation) on baseband signals; and finally outputting output signals of any eight frequency points through the FPGA. The reception system comprises a power division filter module, an analogue-digital conversion module and an FPGA frequency point separation module. According to the invention, echo signals of the radar are subjected to a segmental treatment, and the same treatment is adopted for the signal separation process of each path of the analogue signals after the segmentation. Different clock frequencies are adopted at different treatment stages of the FPGA frequency point separation. According to the broadband channelization reception system of the radar with the external radiation source and the FPGA implementation method, disclosed by the invention, the difficulties of great equipment amount and high development cost when the traditional reception system of the radar with the external radiation source implements synchronous reception of multiple signals of the broadband signals are solved; and complexity and cost of the system structure are decreased.