A method of stabilizing a clinical thermometer and the apparatus thereof are disclosed. The method comprises the steps of pre-heating the surrounding temperature to a pre-set temperature prior to using the clinical thermometer for measuring temperature; and providing compensational temperature by way of heat energy by a control circuit such that the surrounding temperature is maintained and stabilized at the pre-set temperature so as to avoid the change of the surrounding temperature from affecting the measured temperature. The stabilizing devices for a clinical thermometer comprises a clinical thermometer probe head which is a material capable of producing heat energy; and a heating controller connected to the probe head which provides cavity heating for the probe head prior to temperature measuring to the pre-set surrounding temperature, thereby the heating controller causes the surrounding temperature to maintain at a constant and stable temperature such that the precision of measuring is accurate.