In this paper, the design principle and electric circuit of a portable instrument, which is a newly developed device for the biofeedback therapy of skin temperature, is introduced. This instrument is designed in the scope of a research project of nondrug treatment of hypertension.After more than one year s clinical application, we observed an effective physiological decrease of blood pressure of the patients, the systolic and diastolic pressure decreased significantly after two months. So it may be a new ty...