Abstract: In order to increase the intensity of the deuterium beam passing through the accelerating column, and the neutron yield of the neutron generator as well, the Particle-in-cell simulation was used to study the beam transmission in the accelerating column, in which the initial parameters of the deuterium beam were different and the intensities of the deuterium beam were 10-150 mA. The results show that when the normalized emittance of the incident beam at the entrance of the accelerating column is 0.25 πcm•mrad and the Courant-Snyder parameter α=-4, β=60 cm/rad, the deuterium beam of 50-100 mA will match the accelerating column. According to the deuterium beam matching parameters, the extraction system of the duoplasmatron ion source was optimized. The results show that by means of placing two solenoid lenses and an aperture between the extraction system and the accelerating column, D⁺₁ beam of 100 mA can be transmitted smoothly through the accelerating column and the unwanted ions D⁺₂ and D⁺₃ can be eliminated effectively.