Biomass is important precursor to construct environmental functional materials. Polyaniline/lignosulfonate (PANI-LS) was synthesized through one-step method and used as an adsorbent to remove acid red 94 (AR94) dye from aqueous solution. The PANI-LS was characterized using SEM, XPS, FTIR and N-2-sorption analysis. The particles of PANI-LS have been considerably changed after lignosulfonate modified polyaniline. From the batch experiment results, the solution pH plays a significant role during the adsorption. The Langmuir model well describes the adsorption data with the maximum sorption capacity of 10.56gg(-1) (10,560mgg(-1)). Pseudo-second-order model can fit well the kinetic data obtained from batch AR94 removal experiments. The adsorption of AR94 onto PANI-LS is a spontaneous and exothermic process in nature. After adsorption, the adsorbate and adsorbent formed a gel-like composite responsible for the superior adsorption efficiency.