The invention relates to a portable infusion device and belongs to the field of medical instruments. The base is provided with an inlet hole, at least two sinking cavity groups formed by sinking cavities, outlet cavities and an air storage chamber, wherein the number of the sinking cavities contained in each sinking cavity group from left to right is reduced in sequence; inlet cavities and vent holes are formed in the leftmost sinking cavity in each sinking cavity group, and other sinking cavities are provided with air inlet holes and air outlet holes; the inlet and outlet cavities and valve plates mounted in the inlet and outlet cavities form inlet and outlet valves respectively; a main body is mounted on the base and presses a diaphragm on the base, guide holes of the main body and the sinking cavities of the base are symmetrically formed in the two sides of the diaphragm, and piezoelectric stacks in the guide holes press T-shaped pistons on the diaphragm; the diaphragm presses sealing rings into the sinking cavities to form compression cavities; the corresponding compression cavities in each sinking cavity group are connected in parallel to form a compression cavity group, and all the compression cavity groups are connected in series. The top of the main body is provided with a bag cavity provided with an airbag and a medicine bag, a liquid outlet pipe of the medicine bag isprovided with a flow regulating valve and a needle head, and an air inlet pipe of the airbag is connected with the air storage chamber and provided with a switch valve and a deflation valve.