Cubic Al 5 O 6 N nanocrystals were successfully synthesized via a novel strategy called shock wave plasma technique, using trinitrotoluene (TNT) and aluminum powder as raw materials and water as protection medium. The precursor including carbon and Al 5 O 6 N was engendered firstly during the detonation of compound dynamite, and then the pure Al 5 O 6 N nanoparticles were obtained when the carbon was removed through calcining at high temperature. The precursor and the final as-synthesized Al 5 O 6 N powder were characterized by X-ray diffraction (XRD), Raman spectrum and high-resolution transmission electron microscope (HRTEM), respectively. The calcining temperature schedule of the precursor was decided through DTA/TG analysis. The results indicate that the precursor consists of 37.7% carbon and 62.3°C Al 5 O 6 N. After calcining at 600°C for 1h, the average diameter of the as-synthesized Al 5 O 6 N nanocrystal is 30–40nm and the morphology micrograph takes on uniform spherical shape. The lattice parameters are consistent completely with the standard cubic Al 5 O 6 N (JCPDS 48-0686). The well-dispersed Al 5 O 6 N nanocrystals synthesized by shock wave plasma technique can be attributed to the covering of carbon and fast cooling of water medium. A possible reaction mechanism was also proposed preliminarily based on the experimental results.