[Objective] The effects of cellulose-based soil amendments prepared from corn cobs and humic acid on erosion resistance of sandy soil were assessed in order to provide a scientific reference for the management of regional soil erosion problems. [Methods] One or two mixtures of laccase and lignin peroxidase, three enzyme activities, two corn cob biomass addition levels, and a fixed amount of humic acid were used to synthesize cellulose-based soil amendments through aqueous solution polymerization. Infrared spectroscopy was used to characterize enzymatic hydrolysis products and functional groups of amendments. The water retention capacity and network characteristics of the amendments were analyzed based on their swelling characteristics. In addition, the effect of amendments on erosion resistance of sandy soil was also evaluated based on the parameters related to mechanical and water-stable aggregates. [Results] ① The water absorbency of the cellulose-based soil amendments was about 0.61—4.84 times that of pure humic acid-based amendments for which the soil amendment prepared by adding 4 g of enzymatic hydrolysis products of laccase (20 U) and lignin peroxidase (20 U) hydrolysate had the highest water absorbency value (66.7 g/g). The swelling process of the soil amendment corresponded to Schott’s second-order kinetic model. ② Compared with the control group, the addition of 1% amendments (Lac_3-4, Lip_3-4, and LLP_3-4) synthesized by the three different enzymatic hydrolysis schemes increased the soil saturated water content by 20%—60%. LLP_3-4 increased the content of mechanical macroaggregates and water-stable macroaggregates (＞0.25 mm) by 6 and 14 times, respectively, and increased the average weight diameter and geometric average diameter of soil by 70.59% and 46.67%, respectively. The fractal dimension was decreased by 21.36%. [Conclusion] Cellulose-based soil amendments prepared by a dual-enzyme pretreatment scheme can significantly increase the water retention capacity and erosion resistance of sandy soil.