Cellulose-based aerogels (CBAs) were prepared based on Eichhornia crassipes as a raw material and a paper wet-strengthening agent as a cross-linker via a green and simple process. The hydrophobic CBAs had excellent properties, including low density (<0.0055 g cm⁻³), high porosity (>99.6%), excellent oil/solvent sorption capacities (58.06–101.14 g g⁻¹), superhydrophobicity (water contact angle as high as 154.8°), and superior elasticity. Moreover, the absorbed oil could be quickly recovered by squeezing, and the oil sorption capacity was still as high as 75% of the original sorption capacity after 16 cycles. This work provides a facile and cost-effective method to fabricate a novel superabsorbent from waste biomass materials, which is very promising in terms of using waste to deal with oil pollution.