The invention provides a measuring system for thermal conductivity of a non-metallic material in a temperature range of 65-100 K. The system comprises a supporting table, a measuring assembly and a temperature control unit, wherein the measuring assembly comprises a low-temperature source, a heat preservation unit and a pump which are sequentially arranged; the heat preservation unit comprises a heat shielding subunit, a sample subunit, a low-temperature subunit and a heat insulation subunit which are arranged from inside to outside, and all the subunits are arranged on the supporting table through connecting pieces and fixing pieces respectively; a medium adjusting pipeline arranged between the low-temperature source and the pump comprises a low-temperature medium inlet pipeline from thelow-temperature source to the low-temperature subunit, a parallel pipeline formed by a medium outlet pipeline of the heat insulation subunit and the low-temperature medium outlet pipeline of the low-temperature subunit, and a medium inlet pipeline from a parallel connection position of the parallel pipeline to a pump inlet; and the temperature control unit comprises a data acquisition instrument,a computer, a heating meter and a valve.