The invention belongs to a buried pipe compensating device, in particular relates to a buried pipe stretcher. A coil pipe is sleeved to and fixed to an upright post of a bracket which is arranged in a cylinder together with the coil pipe, end covers are respectively fixed at both ends of the cylinder, both ends of the bracket are respectively inserted in pin shaft holes in the end covers, and both ends of the coil pipe respectively extend out from both end holes of the cylinder. The invention has the advantages that the stretching problem of the buried pipe can be thoroughly solved by compensating the stretched buried pipe with the stretcher so as to prevent a pipeline from being twisted, stretched to be deformed, cracked to run water or even broken because of the stretching and the deformation of the buried pipe in the service life of a ground source heat pump and ensure the normal use of the buried pipe.