The invention discloses a microreactor for continuous synthesis of 2-mercaptobenzothiazole. The microreactor comprises a raw material preheater, a micromixer, a filling material reaction tower and a stripping tower which are connected in series to successively complete the processes of preheating, mixing, reaction and phase separation of raw materials, wherein the raw materials comprise aniline, carbon disulfide and sulfur, are separately heated to a respective initial temperature in the raw material preheater, and then mixed in the micromixer in a heat-insulation manner; the micromixer is placed at the bottom part of the filling material reaction tower; a raw material mixture enters from the bottom part of the filling material reaction tower for a reaction; and a product leaves from the top part of the filling material reaction tower to enter the stripping tower, and is separated into tail gas and a crude 2-mercaptobenzothiazole product in the stripping tower. By use of the microreactor provided by the invention, continuous production can be realized; the yield of the 2-mercaptobenzothiazole can achieve 95% or above; the content of resin is less than 2%; and high production efficiency and good product quality are achieved.