Provided is an electric appliance junction box, comprising a mounting box, an adjusting plate inserted into the mounting box, and a drop-proof structure between the mounting box and the adjusting plate. The drop-proof structure is a reversed rack on the inner surface of the mounting box, or a drop-proof rack on the outer surface of the adjusting plate, or reversed teeth on the inner surface of the mounting box and a drop-proof rack on the outer surface of the adjusting plate. A constructor can directly insert the adjusting plate into the mounting box. The drop-proof structure prevents the adjusting plate from being pulled away from the mounting box. The installation process of the adjusting plate is convenient and simple, working strength of the constructor is reduced, and construction difficulty is reduced. When the drop-proof structure is the reversed teeth on the inner surface of the mounting box and the drop-proof rack on the outer surface of the adjusting plate, the constructor can make the drop-proof rack on the adjusting plate meshed with or separated from the reversed teeth on the mounting box through rotating the adjusting plate, so that inserting the adjusting plate into the mounting box or pulling the adjusting plate out of the mounting box by the constructor is convenient.