Adsorption/desorption of Cry1Ab crystal protein extracted from cry 1Ab-transgenic sorghum in six types of soils were determined, and effects of concentration of Cry1Ab protein in the solution and physical and chemical property of 6 types of soils on adsorption/desorption of the protein were studied. Results show that adsorption and desorption of Cry1Ab protein in the 6 soils were obviously different. Paddy soil fromred clay was the highest in Cry1Ab adsorption, and followed by typic podzolic soil, blue purple clay soil, paddy soil from quaternary red clay, yellow loamy paddy soil and paddy soil derived from red sand-stone in a decreasing order, while typic podzolic soil was found the highest in Cry1Ab desorption and followed by blue purple clay soil, paddy soil derived from red sandstone, paddy soil from quaternary red clay, paddy soil from red clay and yellow loamy pad dy soil. A significant positive correlation was found between the concentration of Cry1Ab in the solution added and the adsorption or desorption of the protein by the soils, with coefficients being 0.86 and 0.99, respectively. Effects of organic matter content and pH of the soil on adsorption were posit ive and significant, with coefficients being 0.83 and 0.82, respectively. The correla tion between the adsorption and the content of total nitrogen orreadily available phosphorus was positive, while it was negative between the desorption and the content of total nitrogen, readily available phosphorus or readily available potash. Consequently the adsorption and desorption of Cry1Ab in the soils were controlled jointly by concentration of Cry1Ab protein and physical and chemical propert ies of the soil.