Abstract: The development and expansion of soil cracks in loess are primarily driven by seasonal drying-wetting cycles, rendering the soil susceptible to instability and collapse under extreme rainfall conditions. This study proposes an innovative approach to loess improvement utilizing a complex biopolymer characterized by wide availability, cost-effectiveness, environmental compatibility, and high viscosity. Through systematic indoor drying-wetting cycle tests, the entire crack development process was quantitatively characterized using advanced crack image recognition and analysis software (PCAS). The investigation focused on examining the effects of biopolymer content and drying-wetting cycles on the morphological parameters of fracture networks in modified loess, complemented by SEM tests to elucidate the mechanism of biopolymer-induced crack suppression. The experimental results demonstrate that biopolymer incorporation significantly reduces fracture parameters in treated loess. Specifically, after six drying-wetting cycles, the fracture rate of modified loess decreased by 22.3% and 72.0%, while the fractal dimension reduced by 21.1% and 44.3% for optimal dosages of Xanthan gum (2.0%) and guar gum (1.5%), respectively. Additionally, the water-holding capacity of the samples increased by 43.4% and 15.7%. Notably, at a guar gum content of 0.5%, crack width was constrained to a minimal range, representing a 55.8% reduction compared to untreated loess. The reinforcement mechanism of biopolymer-modified loess is attributed to multiple factors: enhanced bond energy of hydrophilic groups, formation of cementing bridges, pore filling, and development of water-insulating films. These processes effectively limit both transverse deformation and longitudinal settlement of soil, mitigate rapid formation of water content gradient/t/ndifferences, and significantly inhibit crack development and expansion in treated loess. The findings of this research provide substantial theoretical value and practical guidance for engineering construction and slope treatment in ecologically fragile loess regions.