For the further develop and fully make use of bentonite in Tuokexun,Xinjiang,the experiment to modifying the bentonite with the cetyltrimethyl ammonium chloride(CTAC)was made by wet method.The modified organobentonite was characterized by means of X-ray powder diffraction,IR spectroscopy,SEM and laser particle size analysis,the dosage of CTAC on the modification of bentonite was researched.The results showed that when the dosage of CTAC was lower,the surface absorption play a main role.However,when the dosage of CTAC reached to 16%-20%,the CTAC began to penetrate into the lattice layers of bentonite and replace the metallic cation in the lattice layers,with the dosage of CTAC increasing the hydrophilicity of bentonit gradually weakened and its particle size increased.