N-(3-dehydroabietyloxy-2-hydroxy) propyl-N, N-dimethyl (2-hydroxy) phosphate betaine was synthesized through the 3-dehydroabietyloxy-2-hydroxypropyl chloride and tertiary amine intermediate by using dehydroabietic acid as raw materials. The structure of the target product was confirmed by FT-IR, 1H NMR. The surface-active property was investigated by surface tension experiment. The surface activity of the mixed system of the product and sodium dodecyl sulphate (SDS) was determined. The results showed that critical micelle concentration (CMC) of the product was 1.34 mmol•L-1. Strong synergism in product was observed combining with SDS, and the optimum synergism was obtained at the molar ratio of 1:1.