In order to achieve the emulsification viscosity reduction of heavy oil in Huanxiling oil production plant of Liaohe oilfield, the emulsifier solution with the mass fraction of 30%, emulsifying temperature of 50 ℃, emulsifying time of 1 h, stirring speed of 200 r/min, stirring time of 5 min, under the shear rate of 16.9 s－1, the effect of single emulsifier and compounding emulsifier on the stability and viscosity⁃reducing rate of emulsion is investigated. The results show that the optimal compounding mode of the compounding emulsifier is as follow: 0.7% OP⁃12 and 0.8% sodium oleate; the best compound emulsifier and heavy oil could form a stable emulsion, and the viscosity can be reduced from 1 020.9 mPa•s to 72.0 mPa•s, and the viscosity reduction rate reachs 92.95%. The emulsion with the best compound emulsifier and heavy oil has better stability than the single agent OP⁃12 and heavy oil emulsion.