Aluminum is a silver-white light metal, relatively soft, density 2.7g/cm3, melting point 660.4℃, boiling point 2467℃, aluminum and aluminum alloys have many excellent physical properties, has been very widely used. Aluminum has good reflection performance of light, reflecting ultraviolet light is stronger than silver, the purer aluminum is, its reflection ability is better, and the method of vacuum aluminum plating is commonly used to make high-quality mirrors. Vacuum aluminized film combined with polysilicon film becomes a cheap and lightweight solar cell material.