The vertically propagating gravity waves can transport momentum to higher levels in the atmosphere, and they may exert a significant acceleration on the mean flow at the levels where dissipation occurs. In this study, we investigated effects of convectively generated gravity wave drag on mesoscale convective system by implementing two parameterization schemes of convection induced gravity wave drag proposed by Kershaw(1995) and Chun and Baik(1998) into a mesoscale numerical prediction model. Numerical simulations of a heavy rainfall event occurred near the Jiri mountain over the southwestern part of Korean Peninsular on 31 July 1998 are performed with and without convectively generated gravity wave drag parameterization schemes. We will present the difference between two schems and the importance of gravity wave drag on the development and maintenance of mesoscale convective storms associated with a heavy rainfall event.