Growth of AlN hexagonal oriented complex nanostructures were induced by nucleus arrangement under certain conditions in a simple one step halide chemical vapor deposition (HCVD) system. The asprepared AlN nanostructures obtained at different positions from the Al source involve nanomaze, hexagonal nested arrays, hexagonal nanorod arrays with a small pit on the top of each rod and nanoparticle films, respectively. A relevant growth mechanism was suggested and interpreted in detail with a focus on the ‘‘nucleus arrangement’’ combined with preferential growth. Observations of nucleus arrangement events certify the rationality of this mechanism. We found that the variable ratio of AlCl3/ NH3 offers the power to mediate the arrangement of nucleus and crystal growth. There are some differences between the nucleus arrangement mechanism that we put forward here in the HCVD system and the oriented attachment that occurs in solution, because the former possesses a shorter mean free path of the nucleus.