The invention discloses a neighbor discovery method for a mobile ad hoc network based on a directional antenna. By adoption of the neighbor discovery method, the technical problem of low neighbor discovery efficiency of the existing network neighbor discovery method is solved. The technical scheme is as follows: in every neighbor scanning process, each node discovers a certain number of neighbors, so the node can use the existing neighbor information to accelerate the neighbor discovery process. As the existing neighbor information is used, neighbor tables are continuously exchanged, compared with the method in the background art, the method has the advantage that the existing information is fully used, and whether a neighbor relationship exists is directly judged by an algorithm, therefore the time of active scanning detection is shortened. Compared with the background art, the method has the advantages that the neighbor discovery time is greatly shortened, and the neighbor discovery efficiency is improved.