The removal of cationic methylene blue (MB) and anionic acid red 1 (AR1) dyes from aqueous solution was studied using cellulose-g-p(AA-co-AM) bio-adsorbent (CP bio-adsorbent). The CP bio-adsorbent with surface multiple functional groups and macroporous network structure was synthesized via grafting the acrylic acid (AA) and acrylamide (AM) onto cellulose molecules. The adsorption behavior of the bio-adsorbent to dyes in the aqueous solution was studied. The effects of solution pH, temperature, initial dye concentration, and contact time on the adsorption capacity of the bio-adsorbent were investigated. Due to the abundant functional groups and macroporous network structure, the CP bio-adsorbent exhibited remarkable adsorption performance for the removal of type dyes with an equilibrium adsorption capacity of 998 mg·g-1 for MB and 523 mg·g-1 for AR1. The kinetic studies revealed that the adsorption of dyes was exactly described by a pseudo-second-order kinetic model. Comparison with other bio-adsorbents confirmed that the eco-friendly CP bio-adsorbent possessed excellent potential for water purification.