Place the sample to be measured outside the heating plate in a temperature controlled state. One end of the sample is clamped by a clamp, and the other end is hung with a certain weight of silicon code (pre tension; if force is measured, this end must also be clamped). The sample shrinks under heating, and the dry heat shrinkage rate of the sample can be measured by the pulse signal generated by the encoder rotation driven by the friction force between the sample and the surface of the impeller; The dry heat shrinkage force of the sample can be measured through a force sensor.