The invention discloses a pneumatic needleless
injector which comprises a base, an injection component, an air way component, a manual trigger component, an injection dosage regulating component and a needle cylinder component. An impacting
piston of the injection component pushes liquid
medicine in the needle cylinder component to achieve the purpose of injection. High-pressure air is led into the air way component to push the
piston of the injection component to move. The manual trigger component makes contact with a valve element of the air way component through a trigger and a connecting rod to control opening and closing of the air way component. A
threaded rod and a limiting stop block of the injection dosage regulating component are connected through threads, and the
threaded rod is rotated to enable the limiting stop block to move in the axial direction, so that the initial position of the impacting
piston of the injection component is limited, and the purpose of regulating injection dosage is achieved. The needle cylinder component is sealed through a
plunger and a one-way valve structure of a
nozzle, and is used for guiding liquid
medicine in and accommodating liquid
medicine.