The essential oils from the flowers, leaves, barks, roots and fruits of A. brachypus were individually extracted by hydrodistillation, and their chemical constituents were isolated and characterized by means of gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). A total of 160 different constituents accounting for 86.45-96.54% of the total essential oils were identified, and 3 constituents were unidentified (< 0.8%), and significant qualitative and quantitative differences were observed among the oils, in which the yields varied between 0.61-1.83 (mL/100 g dried materials) under the same operational conditions. The oils from flowers, leaves, barks and roots consisted mainly of monoterpenes and sesquiterpene hydrocarbons as well as oxygenated monoterpenes and sesquiterpenes, while the fruit oil consisted mainly of fatty acids and esters. The antimicrobial activities of the essential oils was evaluated against 11 microorganisms (9 for bacteria and 2 for yeast) using agar disc diffusion and broth microdilution methods. The bacteria, including gram-positive bacteria and gram-negative bacteria, were more sensitive to the oils than yeasts.