用氮化硼（ＢＮ）和镉＋氮化硼（Ｃｄ＋ＢＮ）作屏蔽材料的超热中子活化法对我国２０种生物标准参考物质中的碘含量进行了分析。结果可见，含碘量大于１００ｎｇ／ｇ和小于１００ｎｇ／ｇ的固体样品的分析精密度分别为２％－６％和８％－１２％；含量小于１００ｎｇ／ｇ的液体样品的分析精密度为１２％－１８％。用ＢＮ屏蔽的内孔道、Ｃｄ屏蔽的外孔道和Ｃｄ＋ＢＮ屏蔽的外孔道照射的探测极限分别为１０－３０ｎｇ／ｇ、５５－９５ｎｇ／ｇ、２５－６８ｎｇ／ｇ。还对４种国外生物标准参考物质中的碘进行了测定，分析结果与推荐值或文献值吻合。 The iodine content of 20 biological reference materials in China was analyzed by the super-thermal neutron activation method using boron nitride (BN) and cadmium + boron nitride (Cd + BN) as the shielding material. As a result, the analytical precision of solid samples containing iodine more than 100 ng / g and less than 100 ng / g was 2% -6% and 8% -12%, respectively. The analytical precision of the liquid sample containing less than 100 ng / g was 12 % -18%. The detection limits of BN-shielded inner channels, Cd-covered outer channels and Cd + BN-shielded outer channels were 10-30ng / g, 55-95ng / g and 25-68ng / g, respectively. The iodine in 4 foreign biological reference materials was also measured and the results were in good agreement with the recommended or literature values.