In order to solve the problems of high viscosity and poor fluidity of heavy oil in Xinjiang Oilfield, an anionic / nonionic surfactant / polymer viscosity reduction composite flooding system (SP-L) is constructed in this paper. Taking viscosity reduction rate and interfacial tension as evaluation indexes, the optimum ratio of the system is determined by single factor experiment to be 0.25wt % surfactant ( molar ratio of AEO-9 to KPS 1 : 1 ) and 0.1wt % HPAM. The results show that at 53 °C, the oil-water interfacial tension between 0.25wt % ( AEO-9 / KPS ) and heavy oil is 1.1×10-2mN / m, and the viscosity reduction rate of heavy oil is 98.8 %. The O / W emulsion formed by SP-L and heavy oil has an average particle size of 13 μm and a distribution range of 4-30 μm, and can convert oil-wet reservoirs into water-wet (contact angle decreased from 115°to 20.3°). Compare with the commercially available JN-1 viscosity reducer, the viscosity reduction rate of SP-L in the wide oil-water ratio range of 9:1-1:9 increased by 8.6% -19.5%. Displacement experiments show that the oil recovery efficiency of SP-L combined with subsequent water flooding is 22% higher than that of primary water flooding, and 5.1% higher than that of the JN-P system (0.25 wt% JN-1 + 0.1 wt% HPAM). The viscosity reduction composite flooding system constructed in this paper provides technical support for efficient viscosity reduction and enhanced oil recovery of heavy oil in Xinjiang Oilfield.