采用Ｆｏｌｉｎ－酚法及凯氏定氮法对不同产地的４种小牛胸腺素制剂进行了多肽的含量测定，用定磷法测定了该制剂中核酸的含量。结果表明，Ｆｏｌｉｎ－酚法和凯氏定氮法测定小牛胸腺多肽含量有较大差异，制剂中核酸的存在是引起这个差异的主要原因。 Folin-phenol method and Kjeldahl method were used to determine the contents of four kinds of calf thymosin preparations from different areas. The content of nucleic acids in the preparation was determined by the method of fixed phosphorus. The results showed that the content of calf thymus polypeptide by Folin-phenol method and Kjeldahl method was quite different, and the presence of nucleic acids in the preparation was the main reason for this difference.