The invention relates to a reaction kettle used for surface treating agent production. The reaction kettle comprises a kettle body, stirring paddles and a stirring shaft, wherein the stirring paddles and the stirring shaft are arranged inside the kettle body; and the stirring paddles are connected to the stirring shaft. The reaction kettle is characterized in that a plurality of adjusting screws are arranged on the cylindrical surface of the stirring shaft; the stirring paddles comprise paddles and connecting pieces, and the paddles are engaged onto the adjusting screws through the connecting pieces to be connected with the stirring shaft; and moreover, the kettle body is further internally provided with stopping blocks corresponding to the paddles, and the stopping blocks can move in the radial direction of the kettle body. According to the reaction kettle used for the surface treating agent production provided by the invention, the stirring paddles can be blocked, and then the stirring shaft is rotated, so that the stirring paddles and the stirring shaft move in the vertical direction of the stirring shaft through the adjusting screws to realize the adjustment for the height of the stirring paddles, so that the positions of the stirring paddles can be set according to the dosage inside the kettle body, and the reaction kettle is applicable for the stirring of various dosages of surface treating agents.