Out of aluminum surface treatment processes, the buffing and alkaline cleaning process was picked up and the state of the surface was observed through an electron microscope.1) Rate of reflection after polishing varies depending on the kind of abrasive which is used for buffing, and variation of the finishing result can be observed with naked eyes. According to the observation through an electron microscope, less variation of the rate of smoothness between the two treatments mentioned above can be recognized. But it is proved that reflection and refraction are influenced by an abrasive and others which have eaten into Beilby Layer.2) Buffed surface coated with oils and fats, hinders anodic treatment and chemical treatment. It was observed through an electron microscope that how the widely used alkaline cleaning affects aluminun. Concerning the cleaning effects of NaOH, Na3PO4, Na3CO3 and the like that corrode aluminum, it was found that H2 gas which was produced when they reacted on aluminum, acts to take the oil and fat coat film off. Also it was found that the effect of sodium silicate which was used for the purpose of preventing alkaline corrosion formed a solid silicate film on the surface of aluminum and this film was the cause of rough surface from anodic treament.