The invention discloses a device for synthesizing a catalyst by using a novel redox coprecipitation method. The device is characterized by comprising a reaction tank (1), an oxidant solution injectionpump (2), a reducing agent solution injection pump (3), an alkaline solution injection pump (4), a pH probe (5), a temperature probe (6), an upper computer (7) and a magnetic stirrer (8) with a heating function, wherein the upper computer (7) is used for controlling the ion concentration and the redox reaction speed in the reaction tank (1) through control on the propelling speed of the oxidant solution injection pump (2) and the propelling speed of the reducing agent solution injection pump (3), is used for measuring the pH value of a solution accurately through the pH probe (5) in the reaction tank (1), and is used for controlling the propelling speed of the alkaline solution injection pump (4) so that the pH value of the prepared solution is stabilized within a preset range of the setpH value. Through the device, the pH value in the reaction tank can be controlled with high precision, so that the synthesis reaction speed is controlled, the degree of automation is high, and manualerrors are reduced.