The invention discloses an improved type power supply bayonet socket assembly, comprising a bayonet socket fixedly mounted in a wall and a bayonet joint connected to an electric device. The bayonet socket is provided with a hollow groove having a right opening. The left end wall of the hollow groove is provided with a plug-in groove which extends from left to right and is symmetrical up and down,and a transverse sliding groove disposed between two plug-in grooves. The bayonet socket is provided with a longitudinal sliding groove which traverses through the plug-in groove and the transverse sliding groove. A telescoping groove is disposed between the transverse sliding groove and the plug-in groove. The transverse sliding groove is provided with a sliding block in a manner of sliding fromleft to right. The left end of the sliding block is provided with a through slot which runs through up and down. The left end face of the sliding block is provided with a first acting inclined plane in an up-and-down symmetrical manner. The telescoping groove is provided with a telescoping arm in a sliding manner. The end face of the telescoping arm, away from the transverse sliding groove, is fixedly provided with a power supply sheet connected to commercial power. The end face of the telescoping arm, facing towards the transverse sliding groove is provided with a first thrusting inclined plane cooperating with the first acting inclined plane. The longitudinal sliding groove is provided with an up-and-down symmetrical sliding arm in a sliding manner.