Abstract: In this paper,we first analyze the theory of digital detection and the rationale of CORDIC algorithm. On the basis of this,we propose the design scheme of digital detector based on CORDIC algorithm. The design scheme is successfully implemented by FPGA in the project of VXI all-digital IF real-time wideband RF spectrum analyzer design. The experiment shows that the digital detector based on CORDIC algorithm working with digital down converter has high precision and wide dynamic range:±0.01 dB frequency response flatness and 100 dB dynamic range. If the digital down converter works with high frequency resolution FFT based on DSP, the frequency resolution can reach 0.03 Hz.