Abstract: The residue issues resulting from improper use of pesticides occurs frequently in animal origin foods, and its potential risks to human health have drawn attention gradually. This study developed a method based on ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for the simultaneous detection of clethodim and its metabolites, clethodim sulfone and clethodim sulfoxide, in pork, chicken liver, and milk samples. The samples were extracted with acetonitrile, followed by liquid-liquid partitioning with n-hexane and purification with C₁₈ solid-phase dispersion. The results showed that clethodim and its metabolites exhibited good linearity in pork, chicken liver, and milk (R² ≥ 0.9956), with limits of quantification (LOQ) of 0.01, 0.01, and 0.005 mg/L, respectively. The recovery of the method ranged from 84% to 108%, with relative standard deviations (RSD) between 1% and 10%. Compared with other reported methods, the developed method reduced the consumption of organic solvent and achieved higher sensitivity. The established method was used to detect 90 samples of pork, chicken liver, and milk that collected from supermarkets across the country, and no residues of clethodim or its metabolites, clethodim sulfone and clethodim sulfoxide, were detected. The results provide reference for the establishment of standard detection methods for clethodim and its metabolites in animal-derived samples in China.