Abstract：This paper proposes to use sliding singular spectrum analysis(SSA) method for long-term gravity tide correction extraction. The experiment uses 61 days static relative gravity measurement data, and sliding SSA method to divide the data into 52 groups, 47 groups, 42 groups, 37 groups, 32 groups, 22 groups, and 12 groups according to continuous time periods of 10 days, 15 days, 20 days, 25 days, 30 days, 40 days, and 50 days. These data are used for gravity tide extraction experiments. We refer to the theoretical values to select the calculation results of the CG-5 gravimeter software (CG5_Data) and the measured gravity data using Eterna harmonic analysis to obtain the tidal wave parameters, and then we use TSoft software to calculate the results (ET_Data). The results show that when ET_Data is selected as the reference theoretical value, the RMS and STD of the residuals are smaller than those calculated by the CG-5 gravimeter as the reference theoretical value. The STD of gravity tide correction residuals extracted by different methods are all less than 11 μGal. Comparing with SSA method, when the appropriate continuous time period is selected, the extraction of gravity tide by sliding SSA method can reduce the dispersion of the result residuals. The residual RMS of 30-day and 40-day sliding SSA extraction results is 0.219 μGal and 0.602 μGal (CG5_Data) and 0.430 μGal and 0.665 μGa (ET_Data) smaller than the SSA extraction results.