Mobile nodes are interconnected via multihop routing paths that consist of unstable radio links in ad hoc wireless network. Providing QoS routing for such networks is complex owing to imprecise network information, insufficient bandwidth and dynamic topology. Many multipath routing protocols have been proposed to improve network stability and throughput. The sender node discovers multiple disjoined routing paths and spreads traffic among them according to their delay or available bandwidth. For realtime multimedia application, insufficient bandwidth or unstable throughput invite unexpected delays or jitters. Some multipath routing protocols pre-evaluate available path bandwidth and select sufficient bandwidth from them. To minimize the path cost, paths with smaller hopcounts are selected in advance. These selected paths are generally too closed and the total network throughput cannot simple be summed due to “path interference”. Discovering and selecting multiple high-interference paths is ineffectual and the total available bandwidth is not precise. In this paper, we proposed an interferenceaware QoS multipath routing protocol for QoS-constraint multimedia or real-time applications in ad hoc wireless network. Specifically, this paper applied a scheme for evaluating available bandwidth according to the network capacities with different Media Access Control (MAC) protocols. In this paper, we show the “Interference ratio” of multipath and we also evaluate the stability and throughput improvement is assessed through simulations.