Combined with synchronized monitoring techniques, the active constituent in the sample of alkylbenzene sulfonates was separated and purified by liquidliquid extraction method. The results showed that the active constituent with higher purity can be obtained and the content data were more accurate adopting the present optimized purification process. Meanwhile, the residual content of active constituent of alkylbenzene sulfonates in the coexist constituents, such as unsulfonated oil, inorganic salts etc. was less than 1% of the total active amount. The content of active constituent of alkylbenzene sulfonates increased from about 39% to 48% compared to the purification process that is usually used previously.