The gravity variation of the Earth is a comprehensive reflection of the global mass and its motion, and the superconducting gravimeter is capable of observing small changes in the gravity field. In order to characterize the cyclic variations of gravity on interannual scales and the physical mechanisms behind them, in this paper, for the observation data of seven superconducting gravimeter stations, after deducting the instrument drift, synthetic tide, and atmospheric loading effects to obtain the gravity residuals, the normal Morlet wavelet transform method is utilized to identify and extract the signals with the periods of 1 a and 1.2 a, respectively, and the gravimetric factors of the pole tide associated with the Chandler wobble are estimated by the least-squares method. Then residuals are deducted from gravity pole tide, obvious interannual signals common to the stations are extracted, which have periods of 2.3 a, 2.7 a, 3.3 a, 3.7 a, 4.8 a and 6 a, and their corresponding mean amplitudes are obtained in the time domain. The sources of these periodic signals are preliminarily analyzed, in which the variations on the 2 a to 5 a scales have a high correlation with hydrological loads, and the 6 a signals in the residuals are highly correlated with the sequence of gravity variations computed from the GNSS-observed model of the vertical displacements of the Earth's surface 6 a.