The invention discloses a device and method for producing methyl aniline through performing continuous liquid-phase catalytic hydrogenation reduction on nitrotoluene. The method comprises the steps as follows: firstly, nitrotoluene and a precious metal catalyst are put into a hydrogenation reactor for coating backing material, and air in system is displaced completely through nitrogen gas and hydrogen gas in sequence; secondly, a feeding valve is opened, and the nitrotoluene is sent into the hydrogenation reactor continuously, wherein the mass ratio of the nitrotoluene to the precious metal catalyst is 1: (0.001 to 0.005); thirdly, the hydrogen gas is introduced for conducting the hydrogenation reaction, wherein the reaction temperature is 60-100 DEG C and the pressure is 0.5-1.5 MPa; fourthly, a hydrogenated liquid enters a heat exchanger through a circulating pump and then passes through a cross flow filter, and the catalyst and part of the hydrogenated liquid as well as fresh raw materials jointly enter an injector for circulating, while the other part of the hydrogenated liquid is extracted continuously and subjected to follow-up processing for obtaining the methyl aniline. According to the invention, the production period is short, the yield is high, the quality is stable, the production cost is low, the device efficiency is high, and the production continuity is achieved.