With the development of software-based Internet sharing services, there are more and more Internet users who would like to serve as Internet gateways. By considering bandwidth constraints of Internet gateways, how to provide the incentive of Internet connectivity for Internet gateways has become an essential issue nowadays. The previous works were focused on the balancing of network traffic load among gateways and lack to discuss the incentive issue. In the thesis, we propose an auction-based bandwidth bidding mechanism to provide incentive of sharing of Internet connectivity in wireless ad hoc network. By using the developed reward mechanism, the continuity of the system can be also maintained. The simulation results show that our proposed mechanism can effectively provide high profits for Internet gateways and high satisfaction rate on bandwidth for clients.