A ground point fixing device for a power supply module includes an engaging part and a fastening part. The engaging part includes an engaging body, a joining portion and an engaging portion. The engagement body has a body outer diameter and a body surface larger than a grounding hole on a power supply module circuit board. The joining portion is disposed on the body surface and has a joining portion outer diameter smaller than the grounding hole. The engagement portion is disposed on the body surface and around an outer circumference of the joining portion. The joining portion is passed through the grounding hole to be connected to the fastening part, so that the engagement portion of the engaging part is engaged in the grounding hole, and the fastening part and the engagement body of the engaging part are respectively fixed on an upper surface and a lower surface of the circuit board.