Hydrotalcite (HTC), a typical layered compound, is a promising adsorbent for removal of organic pollutants. To partition azo dye from aqueous solution, Mg-Al HTCs intercalated with dodecanoic acid (DA) modifier, DAHTCs, were prepared by ion exchange and calcination-rehydration methods. The structures of HTCs and DAHTCs were characterized by powder XRD and FT-IR techniques. The introduction of DA broadened the spacing of interlayers and provided more space for ion exchange. The effects of pH value, contact time, adsorbent amount, temperature and different intercalated modifiers on the adsorption of azo dye onto HTCs and DAHTCs were determined. The optimum pH of uptake was around 3.0 and all the lower or higher pH values proved to decrease the adsorption properties. The pseudo-second-order model was found to best describe the adsorption dynamics of all adsorbents. Meanwhile, the size and polarity of intercalated modifiers might be crucial for adsorption of azo dye.