Aiming at the problems of taking the bag and weighing with low degree of automation, independent of the bag taking device and a weighing device, decentralized structure and without concentration function, an automatic taking the bag and weighting scheme was proposed based on industrial robot. The device was designed which could cooperate with the actuator of end of the robot, and at the same time achieve taking bag with weighing function. By rational design of moving path for industrial robots, the device was moved to the specified position. By adopting cylinder control device for opening and closing, taking the bag work was done. With application of weighing sensor, weighing function was achieved. Through the device using together with the industrial robots, automation level of packing machine is improved. So the unified structure and function of taking bag and weighing is realized.