The invention discloses a powder quantitative sub-packaging device. The device is characterized by comprising a rack, a main controller, a weighing sensor, a material barrel, a gate valve, a dustproofcover plate and a rotary material receiving mechanism at least provided with two material receiving workstations, the material barrel is suspended on the rack through the weighing sensor, the gate valve is arranged at the discharging end of the material barrel, and the weighing sensor is connected with the main controller; the rotary material receiving mechanism is arranged below the material barrel and comprises a rotary support movably arranged on the rack and open packaging bags respectively positioned and mounted on the material receiving workstations of the rotary support, and one end ofthe dustproof cover plate is connected with the discharging end of the material barrel while the other end of the same is in connection fit with the open packaging bags. The powder quantitative sub-packaging device is simple in structure and convenient to operate, and multiple functions of resisting dust and fixing the packaging bags and the rotary support can be realized through one cylinder.