The invention discloses a full-automatic powder packaging system. The full-automatic powder packaging system comprises a screw filling device (1), a lifting bag clamping and weighing device (2), an automatic bagging device (3), a clamping, transferring and conveying device (4), a bag sewing device (5), a finished product transfer device (6), a powder recycling device (7) and an electronic control device (8). The lifting bag clamping and weighing device comprises a weighing mechanism (24) and a duckbill bag clamping mechanism (25) which can ascend and descend synchronously. A discharging cylinder (13) is sleeved with the duckbill bag clamping mechanism. The duckbill bag clamping mechanism clamps a packaging bag and ascends before filling operation so that a movable material door (156) can be located at the bottom in the packaging bag, the duckbill bag clamping mechanism gradually descends synchronous with ascending of the material level in the filling operation process, and the weighting mechanism conducts weighing at the same time. By the adoption of the full-automatic powder packaging system, powder materials can be weighed precisely, packaging bags are sealed and conveyed, and the full-automatic powder packaging system is especially suitable for premise metering and automatic packaging of extremely fine powder materials.