Abstract: ITER PF conductor is poloidal magnetic field in Tokamak, which is one of the most important parts in the whole device.As one of the numerous methods to ensure the safety, the dye penetrant test is essential.This paper expounds dye penetrant test process of the ITER PF butt welds.With the IIC-d method, the defects in the surface or near the surface can be effectively found. Furthermore, information on the defects such as shape, size, nature as well as the position will be analyzed. This will guarantee the product quality also improve on the defects the production efficiency.