Abstract: The ionization beam profile monitor(IPM) was designed for the beamline of GIC4117 tandem accelerator. The key aspects of the design, such as the calculation of collecting signal intensity, design and optimization of the electric and magnetic field system using a 3-D finite element program are described. The incorporation of an auxiliary magnetic field makes it possible for the IPM to correct the beam orbit automatically. The transverse motion of the ionized electrons is critical to the accuracy of the beam profile measurement. Both theoretical analysis and tracking results of the transverse motion of ionized electrons were done based on the optimized field. The orbit tracking results show that the transverse motion deviation is less than 0.3 mm, which agrees well with the theoretical analysis results.