The Invention provides a head of solar street light to solve such problems of the existing solar street lamp as inconvenient installation, easily damaged battery by high temperature and improper work in rainy days, etc. The head of solar street light invention can be used for replacing all AC street lamps. The invention comprises a crystalline silicon panel, a LED light set, a battery, a control system and a lamp housing; a cavity is concavely provided on the back of the lamp housing, which is covered with the crystalline silicon panel that forms an airtight vacuum insulation zone with the cavity; cavities for lamp and battery, which are insulated through the vacuum insulation zone, are concavely provided on the front side of the lamp housing, and the LED light set and the battery are installed in the lamp cavity and the battery cavity respectively.