The utility model relates to a positive pressure needle free injection precise infusion sleeve upper cover device.The utility model comprises an upper cover and an elastic sealing member.The upper cover protrudes upward and has a dosing pipe.I. infusion tube,And a airway,The dosing tube is provided with a needle free injection interface part.The outer end of the needle free injection interface part is provided with a syringe interface matching a needle free syringe.The elastic sealing member has a compression head.First pressure body,And a compression seat,The pressure head is provided with a sealing part of a sealing syringe interface.When the needle free syringe is pulled out from the syringe interface after injection,The elastic force of the deformed body of the elastic sealing member returns to the original body.And a liquid volume difference is generated relative to the pressure.The liquid volume difference causes a positive pressure to the liquid flowing to the inlet of an injection.一種正壓免針注射精密輸液套之上蓋裝置，包括一上蓋及一彈性密封構件，上蓋向上凸伸有一加藥管、一輸液管、及一導氣管，加藥管具有一無針注射接口部，無針注射接口部之外端具有匹配一無針注射器的一注射器接口，彈性密封構件具有一受壓頭、一壓動體、及一受壓座，受壓頭具有密合注射器接口的一密合部，當結束注射使無針注射器自注射器接口拔除時，彈性密封構件因受壓而發生形變的形體彈力回復至原本形體，而相對於受壓時產生一液體容積差，液體容積差對液體造成流向一注射液內入口的一正壓。
