Objective: Under the guidance of model organism Caenorhabditis elegans with fine olfactory system, small molecular metabolites sensitive to high dose radiation were screened as biomarkers of acute radiation-induced injury, and their metabolic pathways were elucidated by enrichment. Methods: Rats were irradiated with 12 Gy γ-rays to establish an acute radiation injury model, and their urine was fingerprinted using UPLC-Q/TOF-MS. Further, under the guidance of Caenorhabditis elegans as olfactory-sensitive model organism, the key differential metabolites in urine were found as biomarkers of radiation-induced injury. Results: After rats were irradiated, the radiation injury urine showed a difference from control (sham-irradiated) urine, which could be distinguished by Caenorhabditis elegans. Based on metabolomics analysis, a total of 21 key differential metabolites with P value 2 or