In view of the high carbon number of paraffin wax in Yingmai crude oil of Tarim Oilfield，the poor effect of conventional oil-soluble paraffin inhibitor and the difficulty of filling due to the high viscosity at low temperature，an ultra-long carbon chain ternary polymer DMS was prepared by free radical solution polymerization using docosyl acrylate，maleic anhydride and styrene as raw materials，which was suitable for preventing wax deposition in high carbon wax crude oil. The preparation conditions and anti-wax properties of emulsion anti-wax agent HDMS with DMS as dispersed phase and deionized water as continuous phase were emphatically discussed. The results showed that when the mass ratio of T-80 to S-80 was 7∶3 and the composite emulsifier dosage was 10%，the prepared HDMS had good fluidity at 10 ℃ and the viscosity was 24.65 mPa·s. HDMS had good dispersion stability after standing at room temperature for 28 d. The particle size of HDMS was about 2200 nm and the amount of dehydration was only 0.6 mL（the bulk volume was 80 mL）within 1—28 d. When the action temperature was 60 ℃，the action time was 80 min，and the HDMS dosage was 2000 mg/L，the wax prevention rate of HDMS for high-carbon waxy crude oil was up to 84% and had certain wax prevention universality.