An expanding structure of a lamp comprises a seat; a plurality of supporting frames rotatably installed to a periphery of the seat; one end of each supporting frame being connected to the seat and other end of the supporting frame being connected to a respective lamp body; a stand tube extending from an upper end of the seat; a lead passing through an interior of the stand tube; a plurality of adjusting wires extending from a periphery of the stand tube; one end of each adjusting wire being connected to the supporting frame near the lamp body. A ring encloses the stand tube; the ring includes a connecting portion and a clamping portion; the connecting portion encloses around the stand tube. A motor is installed to the retainer. At least one pull wire is installed between the motor and the ring.