The Al-modified Cu/ZnO catalysts were studied by deposition precipitation method, and the catalysts were characterized by XRD, BET and NH₃-TPD.At the same time, the preparation of N,N-dimethylaniline (N,N-DMA) by N-methylation of aniline and methanol was studied. The calcination conditions of the catalysts prepared by the deposition precipitation method were investigated and the process conditions were optimized for the N-methylation reaction. The results show that when pseudo-boehmite is the aluminum source, the molar ratio of Cu/Zn/Al is 1:3:1, the calcination temperature is 400 ℃, the calcination time is 3 h, the reaction temperature is 250 ℃, and the reaction pressure is 1.5 MPa, When the feed space velocity is 0.3 h^_-1, the nitrogen flow rate is 150 mL/min, and the molar ratio of aniline to methanol is 1:7, the N-methylation reaction of aniline was the best, and the conversion rate of aniline reaches 99.8%, N,N -DMA selectivity reaches 92.8%. The catalyst has undergone a 720h stability test. The aniline conversion rate is stable above 99%, and the N,N-DMA selectivity is stable above 90%. The catalyst has good stability.