Abstract: Some reservoirs in western Sichuan are deeply buried about 7000m, the temperatures are higher than 160℃, which require that fracturing fluid system has a good temperature and shearing resistance. By optimizing and evaluating the additive which have a significant impact on the temperature and shearing resistance of fracturing fluid, ultra-high temperature fracturing fluid system is formed which can withstand 160℃ and 180℃ reservoir operation. This formulation can keep enough viscosity above 100mPa.s after it has been sheared for 120 minutes at 160℃ and 180℃. This system can meet the requirement of super-deep fracturing well, and fill in the blanks of ultra-high temperature fracturing fluid in western Sichuan.