A　Cu-catalyzed　aerobic　oxidative　cyclization　of　ss,gamma-unsaturated　hydrazones　for　the　preparation　of　pyrazole　derivatives　has　been　developed.　The　hydrazonyl　radical　promoted　the　cyclization,　along　with　a　concomitant　C=C　bond　cleavage　of　ss,gamma-unsaturated　hydrazones.　This　process　has　been　verified　via　several　control　experiments,　including　a　radical-trapping　study,　an　18O-labeling　method,　and　the　identification　of　the　possible　byproducts.　The　advantages　of　this　reaction　include　operational　simplicity,　a　broad　reaction　scope,　and　a　mild　selective　reaction　process.