Abstract: The field testing equipment of strata thermophysical properties includes fluid circulation line，data collection and control system and electrical control system．An in-situ testing with the rig gets the correlation curve between the inlet and outlet circulating water temperature which gradually turned to be stable with time and quantity of heat transferring of the pipe and soil nearly constant with time．Based on the line-source and cylinder-source heat transfer model， combined with parameter estimation method, the authors get the mean value of thermal properties of soil and well. For soil, the thermal conductivity λ=2.428 W/(m·K)，thermal resistance R=0.102 (m²·K)/W; and for well, λ= 2.164 W/(m·K)，R=0.086 (m²·K)/W．By ensuring testing duration and accurate specific heat capacity，correct parameters of thermophysical properties would be achieved．The results give a basis for designing the groundsource heat pump system.

Key words: in-situ testing equipment of stratigraphic thermophysical properties, mean thermophysical properties parameters, heat transfer model