The invention discloses an assembled buried pipe ground source heat pump system. The system comprises a buried pipe system, a heat pump unit and an air conditioner terminal system; the buried pipe system is formed by serial connection of multiple heat exchange modules; the heat exchange modules comprise buried pipes and heat storage and relief units; the heat storage and relief units are rectangular boxes horizontally placed; the boxes are filled with phase change materials; the buried pipes are arranged in the boxes and wrapped by the phase change materials; the two ends of the buried pipes penetrate through two corresponding surfaces of the boxes to form buried pipe inlets and outlets; the inlet and the outlet of the buried pipe of the heat exchange module in middle are connected with the outlets and the inlets of the buried pipes of the two adjacent heat exchange modules; and the inlets and the outlets of the buried pipes of the heat exchange modules at the two ends are connected with a liquid outlet of a liquid outlet pipeline and a liquid inlet of a liquid inlet pipeline of the heat pump unit. The system is high in heat exchange efficiency, larger in heat exchange area of theburied pipes and simple and fast in assembly.