Abstract: A high-precision frequency measuring system and method. The system includes: an analog-to-digital conversion module for receiving an analog intermediate frequency signal to convert the analog intermediate frequency signal into a digital intermediate frequency signal; a frequency mixing module for generating two orthogonal local carriers to convert the digital intermediate frequency signal to a digital baseband signal; an extraction filter module for performing low-pass filtering and extraction of the digital baseband signal, so as to reduce a data rate; a Fourier transform module for obtaining a frequency domain signal; a frequency measurement module for obtaining a first frequency measurement value; a scanning module for obtaining a scanned second frequency measurement value; and a selector for selecting either the first frequency measurement value or the second frequency measurement value as a result of frequency measurement. The system and method can improve the accuracy of frequency measurement.