Vibration interference is the main factor affecting the accuracy of absolute gravity measurement based on optical interferometry. Novel research on vibration characteristics for absolute gravimeter with the modified ensemble empirical mode decomposition Hilbert-Huang transform （MEEMD-HHT） method is proposed， which is based on the advantages of empirical mode decomposition （EMD） and HHT in the analysis of transient and non-stationary time-varying signals. After the adaptive decomposition of the measured signal， the vibration data is analyzed and studied with the energy spectrum. Experimental results show that this method can effectively restrain the mode mixing， and accurately obtain the intrinsic mode function （IMF） of different frequency bands. The accuracy grade of signal reconstruction is at the level of 10-15. The energy distribution of each frequency band of vibration is accurately obtained after HHT. As a result， 86.95% of the total energy is taken up by the 0.1~5 Hz frequency band， while the rate of 5~20 Hz frequency band is 8.78% and other frequency bands have relatively low energy. Hence， this research can improve the accuracy of absolute gravity measurement and lay the foundation for the design of high-precision vibration absorber.