Abstract: By analyzing the routine Radiosonde data obtained at Wuhan (30.5ºN, 114ºE) from 2000 to 2004, some characteristics of inertial gravity wave in Troposphere and Lower Stratosphere (TLS) were studied, and a strong correlation between the variation of gravity wave energy and jet intensity was found. Similar result of Wuhan was obtained by analyzing the routine Radiosonde data obtained at Haikou (20ºN, 114ºE) and Beijing (40ºN, 116ºE), and stronger correlation was found in higher latitude area. An intensive Radiosonde observation at Wuhan, which lasted 5 days in Jan 2006, was conducted to examine the variation with altitude of gravity wave kinetic energy and potential energy, and it was demonstrated that the excitation of gravity wave in TLS is attributed to jet (zonal wind shear), which suggests that it's a main excitation source of gravity wave in lower atmosphere.