Crosslinked Carboxymethyl Konjac Glucomannan(CMKGM) with substitution degrees ofcarboxymethyl group（DS）0.265, 0.457 and 0.586 were prepared through reaction of monochloroacetic acid, konjac glucomannan(KGM) and epichlorohydrin and used to adsorb Cu(II) from the aqueous solutions of copper nitrate. The effects of pH, adsorbent dose, initial concentration of Cu(II), adsorption time and temperature on adsorption capacity were investigated. The results showed that adsorption capacity increased with an increasing DS of the carboxymethyl groups. Equilibrium adsorption time was 20 min or so and was independent on DS. The adsorption followed Langmuir isotherm equation. Ligand ion adsorption between carboxymethyl group and Cu(II) was thought to be predominate in the process of adsorption according to the relationship between DS and thermodynamic parameters. CMKGM can be used as cheaper and more effective adsorbents.