High-quality　tetrapod-shaped　Al-doped　ZnO　(T-AZO)　nanostructures　were　synthesized　via　thermal　evaporation　of　mixed　Zn　and　Al　powders.　The　effects　of　Al　dopant　concentration　on　the　morphology,　microstructure,　optical　and　field　emission　(FE)　properties　of　T-AZO　were　investigated　using　scanning　electronic　microscopy　(SEM),　X-ray　diffraction　(XRD),　photoluminescence　(PL)　spectra　and　FE　measurement.　It　is　found　that　the　incorporation　of　Al　increases　the　aspect　ratio　of　the　tetrapods,　leads　to　blue-shift　in　the　UV　region,　and　significantly　improves　the　FE　performances.　The　results　also　show　that　tetrapod　cathodes　with　3%　Al　mole　fraction　have　the　best　FE　properties,　with　a　turn-on　field　of　1.33　V/μm,　and　a　field　enhancement　factor　as　high　as　8　420.　The　superior　FE　properties　are　mainly　attributed　to　the　high　aspect　ratio　of　the　legs　in　the　unique　tetrapod-liked　structures,　and　more　electrons　being　induced　in　the　conduction　band　by　Al　dopand.