The present invention is related to a needleless positive-pressure connector, mainly comprising a casing pipe, a connecting pipe, an elastic unit, and a piston. In this connection, the casing pipe and the connecting pipe are interconnected, while the piston and the elastic unit are located within the interior of the casing pipe and the connecting pipe, as well as the piston may be displaced within the casing pipe and the connecting pipe. The piston may be pushed outwardly by the elastic unit to close the needleless positive-pressure connector, when a delivery pipe is not connected yet Moreover, the piston may be pressed by the delivery pipe, such that the piston is pressed inwardly to open the needleless positive-pressure connector, when the delivery pipe is connected.