The test method and system of thermal conductivity to reflect the thermal conductivity of materials are studied. For the existing thermal test equipment, large volume, can only measure the thermal conductivity of the sample, the test results are not accurate and other defects, the design of a flat as a monitoring terminal portable thermal conductivity tester. System based on STM32 controller to detect sample quality, thickness, temperature curve to measure the thermal conductivity, while the picture or data file format stored in the flat test host, to facilitate postprocessing. During the testing process, the system dynamically adjusts the pressure and reduces the influence of temperature caused by temperature expansion. The experimental platform can accurately test the thermal conductivity and stable operation.