The resolution, precision and stability of the radar water -level gauge under the conditions of wide range and large variability were analyzed in this paper. Based on the frequency modulated continuous wave (FMCW) principle, fast Fourier transform and Chip-Z algorithm, fast automatic gain control method, dedicated DSP digital signal processing platform and FPGA large -scale programmable logic chip optimization design were used to meet the wide range and high-precision water level measurement requirements, which has broad application prospects.