The invention provides an automatic plastic bag adsorption and separation device. The automatic plastic bag adsorption and separation device comprises a manipulator, an adsorption mechanism and a separation mechanism, wherein the adsorption mechanism comprises a connection protection cover, a spring, a pressing board, an adsorption piston barrel, an adsorption piston rod, an adsorption suction cup and an adsorption piston rod drive unit; the connection protection cover is connected and fixedly installed on the manipulator through threads and can be driven by the manipulator to rotate; after the connection protection cover rotates, the adsorption mechanism and the separation mechanism are opposite; the separation mechanism comprises a machine shell, a square barrel, a fixing piston barrel, a separation piston rod, a separation suction cup, a square barrel drive unit and a separation piston rod drive unit. A plastic bag is adsorbed by the adsorption mechanism, the adsorption mechanism and the plastic bag can rotate by 90 degrees through the manipulator, and the separation mechanism separates the plastic bag; after the plastic bag is separated, the suction of the suction cup disappears, and the plastic bag automatically falls off. The automatic plastic bag adsorption and separation device is simple in structure, convenient to operate, high in working efficiency, capable of completely replacing a manual plastic bag separation mode, and capable of being embedded into an assembly line for packaging working.