Solar ground-source heat pump (SGSHP) system is unsteady when used to heating. Latent heat storage tank (LHST) was used appropriately in which phase change material (PCM) - CaCl2•6H2O was encapsulated in plastic kegs setting on the serpentine coil. PCM which was as controlling unit of the phase change heat transfer model were solved numerically by an enthalpy-based finite differences method and was validated by experimental data. In order to reflect the effect of the system, two days were chosen to compare the numerical results with experimental data. Inlet and outlet temperature of the water in the LHST, temperature of PCM and storage & emission heat of LHST were measured. The trends of the variation of numerical results and experimental data were in close agreement. Numerical results can reflect the operation mode of the system very well.