Diatomite-attapulgite composite nano-size adsorbent was prepared using natural diatomite and attapulgite through compounding, granulation, calcination and activation. After elementary characterization of this adsorbent by mercury porosimeter, batch tests were carried out to examine its removal mechanism of brilliant green. The influence of adsorbent concentration, contact time, pH, temperature and initial brilliant green concentration on the dye removal were investigated. Increase in adsorbent dosage led to increase in brilliant green adsorption due to increased number of adsorption sites. Maximum adsorption of brilliant green was found at adsorbent dosage of 100 g/L. Adsorption equilibrium attained within 2 h time. The pH variation studies showed that the adsorption process was highly pH dependent. The optimum pH for adsorption of brilliant green was found to be >7. The sorption of brilliant green decreased with the rise of temperature because adsorption process was exothermic. Adsorption isotherm studies showed that Langmuir model fitted the experimental data better than Freundlich model.