Disclosed is a threaded screwable telescopic sealing pipe fitting, comprising a recessed tooth tip end cover threaded pipe composed of a recessed tooth tip end cover (2) arranged at one end thereof and an external threaded pipe (3) connected to the end cover. The recessed tooth tip end cover threaded pipe and a tooth-tip base threaded pipe (7) are sleeved on each other by means of relative screwing, and the length of an external thread of the recessed tooth tip end cover threaded pipe corresponds to the length of an internal thread of the tooth-tip base threaded pipe (7); and a corrugated telescopic pipe (1) is arranged in the recessed tooth tip end cover threaded pipe and the tooth-tip base threaded pipe (7). A clamping ring (11) is arranged on a pipe head at one end of the corrugated telescopic pipe (1) or on each of pipe heads at two ends thereof. The effective telescopic lengths of the tooth-tip base threaded pipe (7) and the recessed tooth tip end cover threaded pipe match the effective telescopic length of the corrugated telescopic pipe (1). The thread screwing telescopic sealing pipe fitting enables the telescopic displacement between the recessed tooth tip end cover threaded pipe and the tooth-tip base threaded pipe (7) by screwing. The sealing pipe fitting is simple and firm in structure, has a large range of a permissible mounting tolerance and is easy to dismount and mount. The threaded screwable telescopic sealing pipe fitting can tightly abut against and seal a vacuum heat collecting pipe with water inlet and outlet pipe heads arranged at two ends thereof.