[Objective] The research aimed to optimize the ultrasonic degradation conditions of linear-chain alkyl benzene sulfonate (LAS) by the orthogonal design and discuss its reaction mechanism.[Method] The effects of ultrasonic frequency,ultrasonic power,amplitude transformer diameter,initial pH value of solution on degradation efficiency of LAS were investigated.The infrared spectrum analysis and chemical analysis were made on original samples and degraded samples.[Result] The orthogonal design test showed that ...