Abstract: In biomedical engineering and micro chemical analysis,the microinjection system based on glass micropipette often have some disadvantages such as seepage or regurgitation during injection because of glass hydrophilicity.It is difficult to detect and control the system and the injection effect from micro pipette is also affected.This paper presents a novel technology of hydropholic treatment.The designated region of inner and outer micropipette surface is treated in a hydrophobic way.The droplet is injected with a spherical shape when liquid flow is driven and controlled digitally,which improves greatly the injection effect,and the amount of injected fluid which may reach an ultra high resolution of the order of femtoliter can be accurately detected and controlled.The validity of the presented method is verified by experiment.