In view of the problem that special FFT processor fail to satisfy the need of the complicated high - speed real - time signal processing in modern radar, four designs of high-speed FFT are presented. Some FFT algorithms are analyzed and compared with each other in speed, resource and complexity, Radix 4 algorithm is selected and CORDIC algorithm is utilized to produce rotation factor whose number and word length are configurable. The validity of the design is validated by the performance analysis and the hardware implementation.