Abstract: The flowability of waxy crude oil from South China Sea under low temperature can be improved with a chemical treating agent. The addition of 150 ppm EVA complex greatly improved the flowability: pour point was reduced from 32℃ to 11.5℃, apparent viscosity lowered by 86.9% and yield stress at 14℃ lowered by 98%. The feed temperature, cooling rate, and the composition and structure of the treating agent which would affect low temperature flowability were investigated. The mechanism of improvement is discussed in the light of wax composition, carbon number distribution of normal alkanes and their susceptibility to EVA of different structures. Cocrystallization is likely to take place only when the ethylene chain in EVA is nearly equal to the normal alkane chain in the crude oil. The crystal forms can then be modified, leading to pour point depression and viscosity reduction.