The opportunistic spectrum access (OSA) techniques in the ad hoc network are researched in this paper.An access scheme is proposed

which can not only suppress the interference between the secondary and the primary users

but also realize the fair and non-conflict resource sharing among secondary users.The solved problems include the spectrum sharing

and the optimal channel selection for secondary users which assure both the interference suppression and the self-optimization.For these purposes

the double selection scheme is built between the secondary users and the available channels.Factors to select channels for secondary users are defined based on the channel available degree.So

the secondary users can select the most appropriate channel according to the service and transfer characteristics.The results prove that the double selection scheme can avoid the conflict and realize the efficient resource sharing.