A power supply includes a metal case, a power conversion module and an insulation connecting plate. The power conversion module is arranged in the metal case and at interval with the metal case. The power conversion module includes a circuit board. The insulation connecting plate is respectively connected with the circuit board and the metal case. The insulation connecting plate is isolated between at least a portion of the circuit board and at least a portion of the metal case. A creepage distance between the metal case and a high voltage area of the circuit board are extended by the insulation connecting plate so as to fulfill the safety requirements.