Simultaneous wind measurements in stratosphere with high-spatial resolution for gravity waves study are scare. In recent years, lots of gravity waves cases were observed by mobile Rayleigh Doppler lidar of University of Science and Technology of China benefiting from the system with excellent performance. In this paper, a brief introduction of the Rayleigh Dopplar lidar system was made. The wind field gravity waves cases in the altitude region 15-60 km were also performed, which were carried out for 2 months started from October 7th, 2015 in Jiuquan(39.741°N, 98.495°E), China. After the 2-D fast Fourier transform of those mesoscale fluctuations of the horizontal wind velocity, the two dimensional spectra analysis and band-pass filter results of these fluctuations exhibited the presence of dominant oscillatory modes with wavelength of 4-15 km and period of around 10 hours in several cases. The observed cases demonstrate the Rayleigh Doppler lidar′s capacity in measuring and studying gravity waves.