The invention relates to the technical field of mobile phone touch screen accessory devices, in particular to a positioning device for a mobile phone touch screen and a face shell. The positioning device has the advantages that automatic attaching can be realized, accurate positioning can be realized, the product quality can be improved, the production efficiency can be improved, and the use limitation can be reduced; and in addition, adsorption of impurities such as dust can be reduced, the face shell can be prevented from being polluted, the attaching yield can be increased, and the use reliability can be improved. The positioning device comprises an operation table, a left front support leg, a left rear support leg, a right front support leg, a right rear support leg, a front cross beamand a rear cross beam, comprises four groups of limiting guide columns, a top plate, a pressing plate, a first hydraulic cylinder, an upper pressing block, a lower pressing block, a sliding plate, arubber acting plate, four groups of buffer springs and a hydraulic station, and further comprises a dust-free box and a dust remover, wherein the dust-free box sleeves the outer side of the top plateand the outer side of the top end of the operation table, and the dust remover is arranged on the inner wall of the left end of the dust-free box.