Abstract: A novel CT self-diverting acid system, applied to acidize uniformly the high temperature/deep burial well and long reservoir interval well, is introduced.Through reducing the impurity content and enhancing the product purity, the acid system's temperature resistance and diversion behavior are increased; the application temperature can reach 150℃, the viscoelasticity can be formed when the acid contacting rock until the acid concentration depressed to 5%.At 150℃, even if the permeability multiples are as high as 40 times, the acid can change the viscosity to block the high permeability zones and to reform the low permeability zones; the used acid can break themselves and the viscosity is below 5 mPa·s. CT self-diverting acid system had been successfully applied in more than 12 wells in Longgang Structure and Feixianguan, the average single well production reached 470×10³ m³/d.