This paper presents a novel micro injector, by which microfluidic delivery, transport and control can be digitally realized in femtoliter scale. The microinjection is based on a new principle that the micropipette is actuated by an actuator, which is located outside the micropipette and may have macro scale dimensions, moving in such a manner that its acceleration changes. When the acceleration is small, the liquid moves along with the pipette; while, when the acceleration becomes large enough, the liquid flows relative to the micropipette. The validity of the presented principle is verified by experiment. Digital microinjection has been realized, particularly under conditions that neither micro moving parts nor embedded micro electric circuits are necessary, hence greatly simplifying the structure and reducing the cost. The microfluidic system can work normally over a rather wide range, even though where very large resistance to flow exists. The amount of injected fluid material may reach an ultra high resolution of the order of femtoliters. The kinds of the fluid materials that can be injected include conventional liquids as well as solid powders, pastes, and other substances of similar characteristics. Furthermore, the digital femtoliter microinjector can be expected for making nano particles.