Based on the long-term observations from Beijing sodium lidar of Chinese Meridian Project, 162 monochromatic gravity waves was distinguished in the sodium layer during the 2208 hours’ observation in 253 nights(from 2010 April to 2011 September). The vertical wavelength, wave period, wave amplitude and its growth factor of every monochromatic gravity wave were precisely extracted with the method derived by Yang et al.(2008). Statistical results reveal that there are systematic relationships between those wave parameters, and they respectively are λ_z=0.226T^0.530_ob, KE=6.66×10^-10 k^-3.091_z and KE=8.97×10^-6 ×f^-1.696_ob. Those results partially agree well with the results predicted by Gardner’s(1994) diffusive filtering theory. However, it is found incorrect to regard the wave-induced eddy diffusivity as the only main damping processes of gravity waves. It is suggested that the damping processes caused by other possible factors also play important roles in the saturation and dissipation mechanisms of gravity waves.