The invention relates to a positioning clamping device for a workpiece with a cavity and a positioning hole. The positioning clamping device comprises a hollow cylinder, a clamping arm, a positioning pin and a driving mechanism, wherein the positioning pin is connected with the hollow cylinder; the positioning pin is exposed on the top surface of the hollow cylinder; a lateral slot is arranged in a side surface of the positioning pin; the lateral slot is communicated with an inner cavity of the hollow cylinder; the clamping arm is arranged in the hollow cylinder and is connected with the driving mechanism located outside the hollow cylinder; the top end of the clamping arm stretches out of the top surface of the hollow cylinder along the lateral slot of the positioning pin; and a pressing head is arranged at the top end of the clamping arm. The positioning clamping device has a simple structure, is convenient to operate and occupies a small space; the workpiece having the structure of the cavity and the positioning hole is effectively clamped; the positioning clamping device is also suitable for the clamping of parts with bigger structures or more complex structures; a welding channel is not plugged; and the subsequent technology, such as welding, and the like, can be smoothly and normally performed.