An information acquisition system includes a transmission device configured to transport a carrier carrying a number of products, an information acquisition device configured to obtain identification information of a corresponding one of the plurality of products when the carrier stops moving, a control device, and a positioning device. The positioning device includes a positioning member, a number of elastic members, a number of blocking members spaced apart and mounted on the positioning member, and a driving member fixedly coupled to the positioning member and configured to drive the positioning member to move telescopically between an extended position and a retracted position. When the positioning member is in the extended position, one of the blocking members blocks the carrier from moving. When the positioning member is in the retracted position, the blocking member that was blocking the carrier unblocks the carrier to allow the carrier to move.