The aim of this work was to describe the development of biogeninc amines and nutritional components in the preparation of Yongchuan koji.Biogenic amines were determined by HPLC.Water content,total acidity and amino acid nitrogen were detected.The results showed that water content was decreased from the initial 46.85% to 33.75%.The content of total acid and amino nitrogen were increased at first and then decreased in the process of natural koji-making.The dynamic change pattern of biogenic amines was as follows: typtamine and phenylethylamine were up to 53.59mg/kg and 52.02mg/kg,respectively.The contents of histamine was decreased from 18.49mg/kg to 0mg/kg.Tyramine was increased to 20.57mg/kg,and then decreased.The content of putrescine was slowly increased.The contents of other types of biogenic amines did not change significantly in the process of natural koji-making.The contents of eight biogenic amines were all lower than 60mg/kg.The sum of eight biogenic amines corresponded with the content of amino nitrogen.