Abstract: To study the binding ability of wheat bran to harmful elements, the ability of adsorption for wheat bran with different particle sizes ( < 0.074、0.074 ~ 0.125、0.125 ~ 0.425 mm) to harmful elements ( aluminum, arsenic, lead) was tested. In the meantime, minerals ( potassium, calcium, magnesium, iron, zinc, copper) contents and harmful elements ( aluminum, lead, arsenic, cadmium, chromium) contained by different-size brans were evaluated respectively in the study.The result showed that the particle size of wheat bran had a significant influence on the amounts of minerals and harmful elements ( p < 0.05) .All the detected contents of minerals were the lowest from 0.074 mm size bran, and the contents of macro element potassium, calcium and magnesium were 7.222, 0.812 and 2.008 g·kg^-1respectively, and the contents of trace element iron, zinc and copper were170, 82.3 and 11.9 mg·kg^-1respectively. However, the contents of harmful elements aluminum, lead, and chromium were the highest that were 13.7, 0.1169, and 0.3150 mg·kg^-1, respectively in these brans.0.125 mm to 0.425 mm size bran contained a lot of macro elements ( The contents of potassium and magnesium were 15.867 and 5.984 g·kg^-1, respectively) , and the detection contents of harmful elements were the lowest, and lead content was only 0.0449 mg·kg^-1. Under the condition of different p H and different particle sizes, the change was consistent for bran adsorption aluminum and arsenic ability. The adsorption capacity increased firstly and then decreased with the decrease of particle size at p H = 2.The adsorption capacity of bran at p H = 7 remarkable increased with the decrease of particle size ( p < 0.05) .And the adsorption capacity under p H = 7 was much smaller than that at p H = 2.The ability of bran for adsorbing lead was greater at p H = 7 than that at p H = 2. And the capacity significantly increased with the decrease of particle size at p H = 7 ( p < 0.05) . Whereas, that binding capacity to lead increased first then decreased with the decrease of particle size at p H = 2.In conclusion, particle size of wheat bran hadremarkable influences on its mineral element content and capacity of binding harmful element.