Ni coatings are prepared on Cu-pretreated anodic Al alloy by electroplating technique in environment-friendly electrolytes with PEG1000 as an additive. Some defects like pores, cracks and even uncovered areas are observed for the sample of the Cu-pretreated anodic Al alloy, and these defects seem to be remedied with the following Ni electroplating as observed from their SEM images; while the covering effect of Ni onto the Cu layer is rather limited as judged by their corrosion current data of polarization test. After adding PEG1000 in the Ni electroplating electrolyte, the obtained coating surfaces are seen smoother and thicker; and most of the tiny particles are seen closely packed together with some bigger particles on them. The diffusion of nickel particles into copper layer are confirmed by the line and mapping mode of EDS element analysis for the Ni–Cu composite coating. Their much lower corrosion current density (Icorr) and higher micro-hardness support the fact that the addition of PEG1000 in Ni plating electrolyte has a function of promoting the refinement of Ni particles and the formation of more compacter, thicker and smoother Ni–Cu composite coating.