The invention discloses a 2-substituted benzotriazinone derivative and a synthesis method thereof. The 2-substituted benzotriazinone derivative of the invention has the structure shown by the following formula (I), and the synthesis method mainly comprises the following steps: adding a compound represented by the following formula (II) in an organic solvent, reacting under the presence of oxygen,and a target crude product is obtained. The method provided by the invention is simple and easy to control, mild in condition, short in cycle and relatively high in yield, and does not need anhydrousor anaerobic conditions. The structures of the compounds represented by the formulas (I) and (II) are as follows: (The formulas (I) and (II) are shown in the description).