The multi-channel parallel diode structure is effective in obtaining X-ray with low energy, large area coverage, and high dose rate in laboratory conditions. In this study, the dose uniformity of single- and five-ring structures was studied based on a point source model. The results showed that the radiation field was primarily focused on the projection position of the ring in the plane near the ring; as the distance increased, the radiation was gradually dispersed to other regions. In the case of single ring structure diodes and z < 15 cm, 80% of the area of the dose homogeneously increased and then decreased with the increasing distance, whereas the total dose in the calculated region decreased gradually. Considering the dose uniformity and total dose, the optimal experimental region of single ring diode radiation field was z = 7-9 cm. A smaller inner ring radius will only enhance the dose near the projection point of the ring; however, the uniformity of the dose on the plane will decrease. A larger inner ring radius will also decreased the dose near the projection point of the ring center. When the outer radius of ring was 10 cm, the optimal inner radius was 8-9.5 cm. Compared with the single ring diode, the dose uniformity of the five ring diode can be greatly enhanced, and the dose uniformity of radiation field and effective experimental region can be improved. Moreover, in z = 11-17 cm, the five-ring dose uniformity did not exhibit significant fluctuations.