The utility model discloses an inverted oscillating type rotary mechanical arm which comprises a connecting seat, a material pawl mechanism, a rotary driving mechanism and a lifting driving mechanism, wherein the material claw mechanism comprises a connecting plate, a material grabbing arm mechanism and a material grabbing arm driving mechanism, the rotary driving mechanism comprises a rotation shaft, a sleeve and a driving mechanism which is used or driving the rotation shaft to rotate, the sleeve is in sliding fit with the connecting seat in a reciprocating way, the lifting driving mechanism comprises a lighting oil cylinder and a connecting plate, the connecting plate is arranged between the sleeve and the connecting plate and is in rotating fit with the rotation shaft, and the connecting plate is fixedly connected with the sleeve. According to the inverted oscillating type rotary mechanical arm disclosed by the utility model, the material claw mechanism, the rotary driving mechanism and the lifting driving mechanism are arranged in a compact way, the material grabbing arm mechanism is arranged on the connecting plate, and an occupied area for the rotation of the material grabbing arm mechanism is small, so that the gyration mechanical arm occupies a small space, and is simple in whole structure, and low in manufacturing cost.