A solar adjustment apparatus includes a control circuit, two optical encoders, two driving modules, and a power circuit. The control circuit is arranged in an upper rail, and the upper rail is fixed on the upper side of a door or window of a building or vehicle. The two driving modules pivot two spools at the same speed. One of the driving modules controls a height of a middle rail in vertical direction of the door or window through one of optical encoders and one of spools. The other driving module controls a height of a lower rail in vertical direction of the door or window through the other optical encoder and the other spool.