The incorporation of inter-session network coding in wireless networks has the potential to remarkably improve the network performance. Unfortunately, the amount of existing coding opportunities in practical networks is limited, which hinders high performance gain by passively using coding opportunities. To overcome this issue, the network-coding-aware routing attempts to promote network coding by creating coding opportunities through constructing specific coding structures in the routing establishment phase. This paper systematically summarizes existing coding structures in inter-session network coding. From the perspective of coding structure, the state of the art of network-coding-aware routing is reported. At last, development trends of network-coding-aware routing are discussed.