Polyaniline with different morphologies doped by nitric acid were prepared using rapid mixture method. Scanning electron microscopy analysis showed that morphologies of polyaniline can be changed from unequal particles to nanowires with increasing the molar ratio of aniline to ammonium peroxydisulfate. The adsorption of rhodamine B dye was carried out using the polyaniline with different morphologies, and the effect of morphologies was studied. The results proved that adsorption of rhodamine B from aqueous solutions using polyaniline is an effective and economical method, and morphologies of polyaniline obviously affect its adsorption performance. The polyaniline nanowires present the best adsorption performance for removal rhodamine B among polyaniline with the three kinds of morphologies.