Mobile nodes are interconnected by multihop routing paths consist of unstable radio links in ad hoc wireless network. It is complex and difficult to provide QoS routing in such network because of imprecise network information, insufficient bandwidth and dynamic topology. For improving network stability and throughput, multipath routing protocols are proposed. A sender node will discover multiple disjoined routing paths and spread traffic into multiple streams according to their delay or bandwidth. For real-time streaming, unstable throughput or insufficient bandwidth will invite unexpected delay or jitter if it is a multimedia streaming. Some multipath routing protocols pre-evaluate available bandwidth of paths and select enough total bandwidth from them if real-time applications demand for QoS constraint. For minimizing the cost of these paths, a path with smaller hopcounts will be prior selected. These disjoined paths are general too closed with each other and the total throughput cannot just be sum up because of "paths interfering". Discovering and selecting multiple high-interfering paths is ineffectual and the total available bandwidth is not precise. In this paper, we proposed an interfering-aware QoS multipath routing protocol for QoS-constraint multimedia and real-time applications in ad hoc wireless network. We apply a scheme to evaluate available bandwidth according to the network capacities with different Media Access Control (MAC) protocols. A concept of "Interfering ratio" of multipath will be discussed and we evaluate the stability and throughput improvement by simulations.