There are rich sensory tactile receptors in human skin. Through touch, the human body can recognize materials with different thermal properties. Flexible thermosensation sensors can simulate the function and structure of human skin. They can be applied to intelligent robots and smart sensing. This article presents a flexible thermosensation sensor based on the constant temperature difference (CTD) method, which is consisted of metal electrodes and flexible polymer films. Combined with the application for machine finger touch and recognition, a “heating-contact” heat transfer model is formulated. The geometric characteristics of the sensor, object, and robot fingers are considered. The numerical Laplace inverse transformation algorithm is used to solve the model. The model is evaluated by finite element simulation and thermal perception experiment. A conditioning circuit for the CTD operating mode is designed. Closedloop temperature difference control is implemented by using the PID algorithm, and disturbance is suppressed by introducing the Kalman filter. The relative error of temperature control is within 3. 0% , and the system can recognize 11 materials with different thermal properties. This flexible system has potential application in fields such as robot perception, wearable electronics, and virtual reality.