Betatrons use magnetic field confinement and induced electric fields to accelerate electron beams, making them move in the accelerator tube and eventually bombard the target to produce X-rays. The intensity and dose rate of X-rays produced by the accelerator are closely related to its magnetic induction intensity. The magnetic induction intensity is affected by many factors such as excitation current, number of coil turns and magnetic pole material. In order to study the influence of permanent magnets on the magnetic field of Betatrons, a model was established by Poisson program, and simulation analysis was carried out. The results show that the permanent magnets with a thickness of 0.5 cm, a coercivity of 1.062 × 10⁶ A/m, and a residual magnetism of 1.401 T are symmetrically placed at the bottom of the upper and lower pole heads, which could effectively enhance the magnetic induction strength at the pole head, and the magnetic induction strength near the electron beam equilibrium orbital is increased by about 18.6%. Under the same magnetic induction strength requirements, the addition of permanent magnets can reduce the required excitation current by about 33.8%. In summary, the method of combining permanent magnets with electromagnets can effectively improve the performance of Betatrons.