In order to understand the heat transfer performance and temperature adaptability of the evaporation section of oscillating heat pipe, the paper presents a 6-elbow temperature adaptive oscillating heat pipe with an outside viewed temperature-controlled reservoir. The effect of heating power and the temperature of the reservoir on the heat transfer performance of the oscillating heat pipe is investigated experimentally using R152a as the working fluid. The experimental results demonstrated that the temperature of the evaporation section will be adaptive to the temperature of the reservoir. When the temperature of the reservoir is 30°C, the temperature of the evaporation section is still close to 30°C, even if the heating power is changed. Under the heating power of 75W, the temperature of the evaporation section changes synchronously with the temperature of the reservoir, and the temperature difference is basically within 5°C when the temperature of the reservoir is changed. With the change of heating power, the thermal resistance of the temperature adaptive oscillating heat pipe changes by 0.286°C/W, which is 3 times of that in the case of oscillating heat pipe without reservoir, and the decrease is more than 23%. Due to the regulation of the saturated vapor pressure inside the oscillating heat pipe, which causes an automatic change in the filling ratio, temperature adaptability is achieved. This paper will provide a new approach to the automatic adjustment of the filling ratio of the oscillating heat pipe during operation.