Abstract: (2, 3-epoxypropyl) dimethyl-ammonium chloride (DMAC) was synthesized with N, N -dimethyl dodecylamine and epichlorohy as raw material in this article Secondly. The LAS was prepared by the DMAC with SL. Through the orthogonal experiment, the optimal preparation condition was investigated: using acetone as the solvent, n (SL)：n (DMAC) was 1：1.1, reaction time was 3h, reaction temperature 55℃, pH value was 12. The nitrogen content of LAS reached 2.25%. The structure of the production was characterized by FT-IR spectrum, UV and elementary analysis. The surface activities of the product were measured: critical micelle concentration (CMC) 3g/L, their surface tension was 21.11mN/m, HLB was 10. The results showed that LAS exhibited a higher surface activity. Key words: Lignin; amphoteric surfactant; physic-chemical property