Abstract: Dye-penetrant testing method is used to detect the surface defects of the aluminum alloy welding seam. The penetrant has a strong penetrating ability, and hence the compatibility of the residual penetrant and rocket fuel is needed to be considered. The Freon in penetrant sprinkler irrigation has pollution to the environment. The detection speed of PT is slow, and the detection results are affected by human factors.Aiming at to solve the above problems, the eddy current array testing technology of aluminum alloy welding seam is carried out, and the results showing that eddy current array testing technology of the aluminum alloy welding seam can replace the Dye-penetrant testing method.