When using global navigation satellite system reflectometry (GNSS-R) signals for tide level inversion, multipath frequencies need to be estimated. The conventional inversion method only estimates the principal frequency, so there are problems such as low data utilization and insufficient temporal resolution of the inversion results. To solve this problem, this paper uses Savitzky-Golay (SG) smoothing filtering to optimize GNSS-R tide level inversion. Firstly, the Lomb-Scargle periodigraph LSP method is used to extract the first four frequencies f1~f4 of signal power, and their corresponding tide level values are inverted. Then, the SG smoothing filter method is used to extract the best inversion results. Finally, 30 days of data from BRST and MAGG stations in France were used to verify the effectiveness of the algorithm. Compared with the LSP method and the window LSP (WINLSP) method, the results show that compared with the LSP method, the average daily inversion values of BRST station and MAGG station after filtering reach 19.30 and 15.23 / day, respectively, which are 34.3% and 19.6% higher. The maximum time interval of the inversion value was 6.63h and 7.07h, respectively, a decrease of 43.2% and 29.4%. RMSE values of 0.3211m and 0.2209m, respectively, are comparable to the LSP method. Compared with the WINLSP method, the average daily inversion values of BRST station and MAGG station after filtering were 60.03/day and 71.17/day, respectively, an increase of 24.2% and 45.9%. The maximum time interval of the inversion value reached 3.08h and 4.50h, a decrease of 25.4% and 28.6%. RMSE values were 0.5222m and 0.3147m, both reduced by 7cm. In general, this method can improve the number of inversion results, improve the utilization rate of data and the temporal resolution of tide level inversion under the premise of ensuring accuracy.