Abstract: Xinjiang Bulunkou-Gongeer hydropower station is located in the heartland of West Kunlun Mountains. With the action of the old and new tectonic movement， there exists high temperature in the front section of the diversion tunnel (the measured temperature is about 105℃), which has great impacts upon construction progress and the durability of the supporting structure. An analytical method has been used to make studies of the temperature distribution and stress characteristics of the surrounding rocks and the supporting structure. Firstly， both the transient and steady methods are used in studying the temperature distribution. Furthermore， the stress characteristics of the surrounding rocks and the supporting structure are also investigated in consideration of the coupling effects of temperature and stresses. Lastly， the spacing of the contraction joints to the lining structure is designed in this paper. The research results show that the stresses of the supporting structure are characterized by near-linear distribution， but the stresses of the surrounding rocks have obvious non-linear characteristics during the diversion tunnel operation period. When the cold water flows through the diversion tunnel， the temperature in the inner wall plummets and the variation amplitude is about 60℃.