Abstract: Semicarbazide (SEM) is a toxic substance, which is a marker residue to determine whether Nitrofurazone is used illegally or not. To explore the detection of SEM in Crustacean aquatic products, we detected the SEM content of M. rosenbergii by High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS/MS). The results show that SEM was detected in different parts of M. rosenbergii, higher in the cephalothorax and shrimp shell Average: (32.02±3.75) and (26.85±13.90) μg·kg⁻¹, but lower in the muscle and liver Average: (1.35±0.67) and (5.56±0.87) μg·kg⁻¹, and all exceeded the residue limit standards in China (1 μg·kg⁻¹). The SEM content in the shrimp shell and shrimp meat increased with the prolongation of storage time, but that in the shrimp shell was higher than 1.0 μg·kg⁻¹. Different storage temperatures had a little effect on the SEM content of M. rosenbergii. Therefore, when taking SEM as a marker for Nitrofurazone residue detection of M. rosenbergii, the detection time and background content factors should be considered so as to avoid false judgment; and in order to ensure the authenticity and accuracy of the test results, the crushed shell should be avoided in preparing samples.