Abstract: The Fengcheng formation in Mahu sag in Junggar basin develops a thick?bedded tight dolomite reservoir, which is a typical oil reservoir with lower generation and upper accumulation. The tight and rigid lithology is sensitive to the fluid in a wellbore and resulted in difficulty for reservoir stimulation. The reservoir is characterized by very high salinity and containing B, Ti and Zr heavy metal ions in the formation water, which lead to the incompletion of gel breaking and the difficulty of fluid returning. Also, the reservoir has the features of “three highs and one deep”, namely, high pressure coefficient (>1.5), high temperature(>100℃), high closure stress (>90 MPa) and large buried depth (>4000 m). The complexity of the stress distribution and the development of natural fractures have caused fracturing filtration, varied fracture shapes, narrow fracture width and easily sand plugging. Aiming at these difficulties, this paper presents a new kind of fracturing fluid with high?temperature resistant and acidic hydrophobic association to solve the post?fracturing gel?returning problem. In addition, by establishing the formula of rock mechanics parameters of static and dynamic conversion and studying screening approach of proppant grain size, this paper establishes the empirical equation for prediction of the formation fracture pressure, thus systematically optimizing the fracturing design program. At present, 23 field tests have been implemented, and the success rate of the projects has increased from 50% to 100%, then the average proppant volume has increased from less than 35 m3 to 42.5 m3