Skin patch drug infusion device and drug filling method thereof

A skin patch drug infusion system, comprising:

• an infusion mechanism module, wherein the infusion mechanism includes:
• a reservoir, for accommodating a drug to be infused, and provided with a drug inlet and a drug outlet;
• an infusion needle, wherein one end of the infusion needle is communicated with the drug outlet of the reservoir, and an other end of the infusion needle is inserted subcutaneously implanting drug infusion;
• a control mechanism module, worked collaboratively with the infusion mechanism module to regulate drug infusion;
• an adhesive patch, for attaching the infusion mechanism module and/or the control mechanism module to a skin surface;
• and
• a filling module, for filling the drug to be infused into the reservoir via the drug inlet, wherein a volume of the filling module is deliberately designed to be greater than a volume of the drug to be infused, and an excess space in the filling module is used to generate negative pressure to extract air in a fluid path.