Abstract: In order to realize the quadrotor's automation and informatization in transportation，we designed and realized a quadrotor which could track and grasp target automatically and then carry it to the specified place．By applying the control theory of quadrotor，the quadrotor could be able to judge its position in real time using computer vision technology and acquire its amplitude with a sonar sensor，thus adjust its flying amplitude and attitude angel with the PID ( Proportion-Integral-Derivative) controller． Thus，the system finished automatically tracking and target identification using camera and drove a manipulator to accomplish target grasping and releasing． The result shows that the quadrotor could keep its flying height at 1 m，and fly at the speed of 20 cm /s． The machine could recognize and grasp a cylindrical target of which the radius is 4 cm and the length is 8 cm． The whole process can be finished in 50 s．

Key words: quadrotor, automatic tracking, object extracting, computer vision, PID controller