In this paper, we'll propose an approach to support QoS and multimedia applications in ad hoc wireless networks. An ad hoc network is a collection of mobile stations forming a temporary network without the aid of any centralized coordinator and is different from cellular networks which require fixed base stations interconnected by a wired backbone. It is useful for some special situations, such as battlefield communications and disaster recovery, search and rescue. The approach we provide uses the CSMA/CA medium access protocol and additional reservation and control mechanisms to guarantee quality of service in the ad hoc network system. The reason we choose the CSMA protocol instead of other MAC protocols is that it is used in most of the current wireless LAN productions. Via the QoS routing information and reservation scheme, network resources are dynamically allocated to each multimedia application.