A high-resolution mass spectrometry database was established for kudzu powder and its common adulterants (cassava and corn starches) to detect adulteration in kudzu powder products, with characteristic compounds identified for the three starch products. The samples were ultrasonically extracted with methanol-water (7:3, V/V) and analyzed by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. The mass spectrometry data were subjected to multidimensional analysis using the Progenesis QI software to screen for differential metabolites between kudzu starch and its adulterants. The differential compounds were identified by integrating accurate molecular weights, fragment ion information, and matches with both online databases and the literature. Principal component analysis (PCA) demonstrated clear separation among kudzu, cassava, and corn starches. Ten characteristic differential components were screened and identified through the Progenesis QI software, including six components (e.g., puerarin, 3′-methoxypuerarin) specific to kudzu starch, with epicatechin and scopoletin serving as markers for cassava starch, and ferulic acid and indole-3-acetic acid as markers for corn starch. An identification method based on high-resolution mass spectrometry and metabolomics was successfully established in this study, in which key characteristic compounds distinguishing kudzu powder from its adulterants were screened and identified. These findings provide a reliable technical solution and theoretical foundation for the rapid, high-throughput, and high-accuracy detection of cassava starch and corn starch adulteration in kudzu powder.