Objective This study reveals controlling mechanisms and relative importance of interface roughness， particle gradation， and coupling effects of temperature and thickness on the development of soil desiccation cracking， providing a theoretical basis for preventing engineering hazards such as anti-seepage failure and mechanical instability of soil masses. Methods Sediments from Qingshitan Reservoir in Guilin were selected as test materials， and a series of laboratory drying model tests were designed and conducted covering different particle gradations （intrinsic components）， bottom interface roughness （boundary conditions）， and drying temperatures and initial soil layer thicknesses （environmental and geometric conditions）. High-precision imaging equipment was used to record the whole process of water evaporation and crack evolution in soils. Digital image processing techniques were applied to perform binarization and skeletonization of crack networks to quantitatively extract characteristic parameters such as crack ratio， average crack width， and fractal dimension. Range analysis was employed to systematically calculate and compare the contribution weights of different factors to desiccation cracking development. Results 1） Interface roughness was the primary controlling factor of crack network development and morphological evolution， with a contribution weight of 57.08% to crack ratio. Increased interface roughness significantly enhanced geometric complexity and topological connectivity of crack networks and induced significant curling at soil edges. 2） Particle gradation， acting as an intrinsic factor， had a contribution weight of 26.98%. An increase in fine particle content showed significant positive correlations with crack ratio， crack width， and fractal dimension， fundamentally determining volumetric shrinkage potential and final cracking modes of soils. 3） The combined contribution rate of temperature and thickness was approximately 16.00%. Specifically， the contribution weight of initial layer thickness （9.18%） was significantly higher than that of the drying temperature （6.76%）. The former dominated macroscopic distribution patterns of cracks primarily by constraining the release range of tensile stress， while the latter exhibited relatively complex non-monotonic variation characteristics. Conclusion The dominant factors controlling soil desiccation cracking development are interface roughness and particle gradation， while environmental temperature and initial thickness play secondary synergistic roles. The results provide a scientific basis for the prevention and control of cracking hazards， material improvement， and construction process optimization of anti-seepage soil masses in practical geotechnical engineering.