Abstract: Based on GB 7494-1987, and using the linear module automatic control system and complex pipeline switching technology, the basis of multiported valve, the on-line, continuous and multiple samples extraction of anionic surfactants is realized. The results showed that:the concentration range of the anionic detergent online extraction analysis systemwas 0.1~2.0 mg/L, the linear correlation coefficient was 0.999 9, the detection limit was 0.035 mg/L, the actual recovery rate was 80%~115%, the relative standard deviation was 0.57%~5.73%, the actual detection time of each sample was 25 min, and the maximum samples number was 20 bits. The whole extraction process was carried out in an airtight container. The temperature and humidity can be controlled within a constant range. The operator would not contact with chloroform reagent. Comparing with the manual extraction, the whole extraction process is fast and efficient, It can fully meet the requirements of batch quantity analysis and real-time monitoring of water samples.