Positive-pressure joint for infusion without needle

The utility model relates to a positive pressure connector used for needless infusion, which comprises an outer shell with a hollow inner part, a connector with a hollow pipe cavity, a movable core with a hollow cavity body and an elastic body. The right end of the connector is provided with a ring-shaped groove which is connected with the outer shell; the movable core is sleeved in the ring-shaped groove; the outer diameter of the end of the movable core near the connector is bigger than that of the end away from the connector; the movable core is in an arc surface from the end near the connector to the end away from the connector; when the movable core is positioned at the original position, the arc surface and the end away from the connector fit close with the inner wall of the outer shell; the elastic body is arranged in the ring-shaped groove, one end contacts with the connector, and the other end contacts with the end of the movable core with a bigger diameter; a channel communicated with the inner cavi