The invention relates to a generation device of quantum entanglement among three atomic ensembles, and mainly aims to solve the existing technical problem of probability preparation existed by quantum entanglement among a plurality of atomic ensembles. The invention adopts the technical scheme that the generation device of quantum entanglement among the three atomic ensembles comprises a light source unit, nine acousto-optic modulators, three sets of optical parametric amplifiers, a beam coupling system, the three atomic ensembles, three sets of optical filtering systems and an entanglement measurement system. Under the light writing action of quantum memory, orthogonal component quantum states of three entangled light pulses are mapped into collective spin waves of the three atomic ensembles, and quantum entanglement among the three atomic ensembles is certainly established; then, under the light reading action of quantum memory, the collective spin wave quantum states of the three atomic ensembles are mapped into the orthogonal component quantum states of the three release light pulses, and quantum entanglement among the three atomic ensemble is certainly verified through measuring correlative characteristics of the orthogonal component quantum states of the three release light pulses and the collective spin waves of the three atomic ensembles.