In view of the slowing expansion problem for the past harvesting robot’s electric push rod joint.This paper will adopt pneumatic draw stem instead of the original electric putter to improve the rapidity of servo system. Using VFW(Video for Windows) image acquisition system to access to the video buffer without generating the intermediate files,which can ensure high real-time performance. By monocular vision system to realize cylinder tracking control experiments for the fruit center position. Experiments verified the quickness and accuracy of the pneumatic servo positioning system.