The present utility model discloses a safety mechanism for a retaining needle and a retaining needle having the safety mechanism. The retaining needle comprises a hollow handle and a needle seat at least partially disposed within the handle for receiving a puncture needle, the safety mechanism comprises: a snapping step disposed at an inner side of the hollow handle； at least one elastic arm radially spreading outward disposed on the needle seat, an end portion of the elastic arm has a snapping portion radially protruding outward, the snapping portion being engaged with the snapping step； a button disposed on a distal side portion of the handle； the button, when being depressed, pushing the elastic arm along a radial inward direction, such that while the snapping portion of the elastic arm is disengaged from the snapping step, the needle seat and the puncture needle stretching outside of the handle are retracted into the hollow handle by virtue of vacuum within the hollow handle.
