This paper aims to study and analyze the subject of optimal pretreatment processes for metal plating on engineering plastics, especially on ABS-PC blend resin. For ABS-PC blend resin, preetching process is employed to swell and soften the surface of plastics by immersing in the organic solvent mixtures, just before etching process. Senditizing process is also employed to increased wettability and adsorption of catalyst, just before activating process. If sensitizing treatment process is not carried out, adhesion strength is very poor. In the result of SEM and surface roughness measurement preetching treatment enable the surface condition to be very poor. In the result of SEM and surface roughness measurement preetching treatment enable the surface condition to be very rough and adhesion strength to be good. It shows that the relation between surface condition of plated article and adhesion strength depends markedly upon molding condition of ABS-PC blend resin. It, by means of ESCA, aims to what kinds of and how much quantity of the metal elements remain on the resin surface after pretreatment processes. Cr residue does not affect adsorption of Sn and Pd remarkably but adhesion is reduced, owing to obstruction between resin surface and Pd.