Mutagenic and/or carcinogenic heterocyclic aromatic amines -HAAs- have been found in livestock and poultry products. IQ-type HAAs are formed by heat- induced non enzymatic browning, known as Maillard reaction which involves creatine, amino acid and sugars. Whereas amino-carbolines are mainly formed by pyrolysis of amino acids and proteins at the temperature above 300℃. It is shown that the increase of processing temperature and prolong processing time can result in a dramatic increase in the amount of HAAs. Some natural plant extracts and antioxidants were found to be promising inhibitors to HAAs. In this paper, the structures, classification, content of HAAs as well as the influencing factors are introduced, the formation and inhibition of HAAs are emphasized.