The utility model relates to a positive pressure needle free injection T-joint device.Including a T-shaped pipe and an elastic sealing member provided therein,The T-tube has a needle free injection interface.The outer end of the needle free injection interface part is provided with a syringe interface substantially matching a needle free syringe.The elastic sealing member has a compression head.First pressure body,And a compression seat,The compression head is provided with a sealing part of a substantially closed syringe interface.There is a flow space between the external surface of the pressure body and the pressure seat and the internal surface of the T-tube.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T型接頭裝置，包括一T型管及設置於其中的一彈性密封構件，T型管具有一無針注射接口部，無針注射接口部之外端具有實質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，受壓頭具有實質密合注射器接口的一密合部，壓動體及受壓座之外表面與T型管之內表面之間具有一流動空間，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。
