Abstract: A solid surface frequency modulated continuous wave (FMCW) radar signal model was built to solve the range ambiguity problem of wideband and low signal-to-noise ratio (SNR) FMCW signal under severe measurement conditions. Based on prior information, a distanee inversion method was proposed, which contained signal pretreatment, band intercepting, and energy weighting. Actual data processing results show that the SNR of the frequency spectrum rises from-5.55 to 8.32 dB after pretreatment. The index of similarity of the stock level shape increases from 0.46 to 0.71 and 0.79 by band envelope interception and least squares interception, respectively.