Abstract: A novel cellulose nanofibers(CNF) aerogels were prepared based on the spherical cellulose nanofiber gel modified with 3-(2-aminoethylamino) propylmethyldimethoxysilane (AEAPMDS) in combination by solvent displacement and freeze drying. The change of its N content was investigated under different reaction conditions. The resultant spherical nano cellulose aerogels were characterized with respect to microscopic morphology, structural characteristics, mechanical properties and CO₂ adsorption properties. The results show that the best preparation condition of the AEAPMDS-CNF aerogel is for 10 h at 90℃ and 12wt% AEAPMDS. The prepared AEAPMDS-CNF aerogel is a mesoporous material with 3D network pore structure, light mass (ρ ≤ 0.0573 g·cm^-3) and high porosity (ε>90%). Its compressive strength can reach 0.46 MPa with a high CO₂ adsorption capacity of up to 1.54 mmol·g^-1. It is a promising material for CO₂ adsorption in the future.