Semicarbazide has become an important pollutant in the environment, but there was no comprehensive literature on its advances. In this review, the source, biotoxicity and detection methods are summarized. Among the sources is the material of chemical reaction, a metabolite of nitrofurazone, food processing (production by azobisformamide and hypochlorite treatment), endogenous substances, etc. Semicarbazide is demonstrated to be accumulative and reproductive toxicity, mutagenicity and genotoxicity, endocrine disruptors, and neurotoxicity. There are still many controversies on the effect of genotoxicity and no clear result on the carcinogenic mechanism. HPLC-MS/MS is the mainstream of the detection methods. Other methods, including HPLC, immunoassay method, biosensor method, electrochemical detection, capillary electrophoresis technique, and spectral techniques mainly, have become less and less in recent years. On all these counts, to reduce the content of semicarbazide in the environment, the key is to control the use of nitrofurazone as the banned drug effectively. Meanwhile the toxicity data should be supplemented to reveal its toxic mechanism.