Since the human thermoregulation and heat transfer processes are altered in hypobaric hypoxia indoor environments (HHIE), investigations on thermal physiology for people under low air pressure are necessary. The purpose of this study is to establish a new regional thermal manikin prototype and verify its temperature prediction efficiency under HHIE. A previously improved Tanabe model was integrated in the prototype to control the skin surface temperature, aiming to adapt to heat transfer changes in HHIE. Temperature control performances under the constant skin temperature (CST) mode were tested with a target temperature of 25 °C. Simulation accuracy verification experiments were conducted under room temperature and different altitudes and air pressures. Human thermal physiology experiments measuring forearm skin temperature were also conducted under the same indoor conditions. Through analysis of manikin and human skin temperature data, the temperature control accuracy of the self-adaptive thermal manikin was validated.