Abstract: Heavy oil produced in No.Ji-7 Wellblock, Eastern Zhungeer Oilfield, Xinjiang, has high viscosity, which results in wellhead's high back pressure and high energy comsumption in gathering process. Referring to the heavy oil, indoor screening tests on emulsifying thinner is made to, choose OP-10 thinner as the emulsifying candidate for No.7- Ji Wellblock, and its application conditions are determined as optimum dosage of 0.75%, optimum emulsifying temperature of 50 ℃ and optimum water mixing amount of 30%, in this way, the apparent viscosity of heavy oil at 50 ℃ is decreased from 1 979 mPa·s to 105 mPa·s, with a reduction rate of 94.7%. The simulation calculation results of application PIPEPHASE software show that if emulsifying thinner is used in gathering process, the gathering distance of heavy oil for No. Ji-7 Wellblock will reach up to 2 216 m, and the inlet viscosity of emulsion is at 496 mPa ·s, which extends the gathering distance with good flowability for the emulsion.