Abstract: In order to explore the difficulty that the determination of aniline recovery rate in soil is low,the author addressed the problems in the pretreatment stage of Determination of Aniline and Benzidine in Soil and Sediments by Liquid Chromatography-Triple Quadrupole Mass Spectrometry (Draft for Comment), based on the optimization of some pretreatment conditions,the effects of soil adsorption, internal standard addition at different stages, and addition of reducing agent (sodium thiosulfate pentahydrate) and ammonia on the recovery rate of aniline were studied.It was found that: Soil adsorption is an important factor leading to the low recovery rate of aniline. Compared with blank addition, the recovery rate of sandy loam matrix with a certain amount of organic matter was reduced by 42.05%-60.89%. The addition of internal standards at different stages will have a significant impact on the recovery rate of aniline,which is mainly due to the matrix adsorption and volatilization loss during the pretreatment process. The addition of reducing agent and ammonia water had no significant effect on the recovery rate of blank spiked aniline, but for sandy loams with a certain amount of organic matter, the recovery rate of aniline spiked after adding ammonia water increased by 59.57%,which had a significant effect.