The utility model relates to an infusion system capable of preventing liquid medicine from residue. The thickness of a bottle stopper of an infusion bottle is smaller than the length of a syringe needle part of an infusion set; at least one concave pit is arranged on a plane of the bottle stopper of the infusion bottle in contact with liquid in the infusion bottle; a circular ring-shaped protuberance corresponding to the concave pit is formed on a plane of the bottle stopper in contact with air; the syringe needle part of the infusion set is inserted from the circular ring-shaped protuberance; and lowest points of all concave pits are communicated through a runner. The utility model overcomes the problem of liquid residue, is convenient to operate, and has a simple structure, and furthermore, doctors and patients use the infusion system more with less time and effort safely and conveniently.