The invention relates to an N-substituted dioxazine compound as well as a preparation method and application thereof. The N-substituted dioxazine compound has the following chemical structure general formula (I), wherein Ar in the chemical structure general formula (I) is a benzene ring, a naphthalene ring, and a pyridine or pyrimidine ring system. The compound is prepared with the following two steps: (1) taking 2-(benzyl)-7-benzindene[1,2-e][1,3-4] dioxazine-2,4a(3H,5H)-dicarboxylic acid-4a-methoxycarbonyl group and hydrogen as raw materials, taking Pd/C in solvent a as catalyst a, and carrying out hydrogenation, thus obtaining an intermediate B after reaction is finished; (2) taking (carbonylchloride) (aryl) methyl carhamate as the intermediate C, and carrying out (carbonylchloride) (aryl) methyl carhamate with the intermediate B obtained in the step (1) in the presence of a catalyst b in the solvent b; and obtaining the product N-substituted dioxazine compound. Compared with the prior art, the insecticidalactivity on the armyworm by the N-substituted dioxazine compound is 80-100%.