The convection-excited gravity waves can transfer momentum and energy to the middle atmosphere, and it is very important to accurately obtain the main characteristics of gravity waves for studying the dynamics and thermodynamic structure of the middle atmosphere. Based on the constellation observing system for meteorology, ionosphere and climate (COSMIC) data and the weather research and forecasting model (WRF), the gravity wave excited by a convection over North China on 4 August 2010 was investigated in this paper. The results show that the gravity waves excited by the convection were mainly low and medium frequency wave in the stratosphere, and the vertical and horizontal wavelengths were 9-11 km and 650-800 km in the stratosphere, respectively. About 62% of momentum was aggregated in 15-25 km height of the lower stratosphere. During the occurrence of convection activity, the potential energy per unit mass of gravity wave in the lower stratosphere always maintained a large value, while in the upper stratosphere it decreased rapidly when the convection weakened, and it increased rapidly with the next convection once again. The response of potential energy per unit mass of stratospheric gravity wave to convection at different heights was mainly related to the development height of convection and the background wind field. When the convection development was shallow, the excited gravity wave was easily dissipated in the low-level westerly wind. However, when the convection developed to 16 km or higher, the excited gravity wave was close to the zero wind layer, and it could be rapidly uploaded in the easterly wind, resulting in rapid increase of gravity wave potential energy per unit mass in the upper layer.