Two methods,gas chromatography-mass spectrometry（GC-MS） and liquid chromatography-tandem mass spectrometry（LC-MS/MS） were proposed for the study on the trace components in tainted starch noodles（fake starch noodles） and noodles made from real sweet potato.Some impurities such as phenol and pyrrolo［1,2a］pyrazine-1,4-dione,hexahydro-six were detected by GC-MS,and tartrazine,sunset yellow and brilliant blue were found by LC-MS/MS,while such components would not exist in real sweet potato.The existence of these substances could be used to confirm weather starch noodles were tainted or not.