Due to the broadcast nature of the wireless medium, when a source sends a packet to a destination, all its neighbors and neighbors of relay nodes from source to destination can overhear the packet, so there will be many copies of the packet in the network. How to use these copies to increase the coding chance is worth studying. In this paper, a Real-time and High Coding Opportunity discovery scheme (RTHCOD) is proposed, which is realized by appending the current node ID and all its 1-hop neighbors' IDs to the packet. RTHCOD enables the next hop relay node to know which nodes else have already overheard the packet, so it can discover the potential coding opportunities as much as possible. RTHCOD expands the region of discovering coding chance to n-hops, and has more opportunities to execute network coding operation in each relay node. At last, with comparison and analysis between RTHCOD and COPE[2], RTHCOD is proved to be much more efficient.