To clarify the influence of sand incorporation on the evaporation cracking behavior of clayey soils, indoor experiments were conducted to simulate arid environments to induce the development of desiccation cracks in clay samples. Quantitative analysis of the formed cracks was performed using digi-tal image processing techniques. Based on the staged morphological characteristics of crack evolution, a classification nomenclature system for soil desiccation cracks was established. The present study investigated the effects of temperature (40 to 60 ℃), sand content (0% to 30%), and sand particle size (0 to 2.0 mm) on clay desiccation cracks. The experimental results demonstrate that: (1) Desiccation crack development in sandy clay progresses through three distinct stages: formation, development, and stabilization. Sand particles reduce the rate of moisture evaporation in clay, thereby diminishing fluctuations in the surface stress field and decelerating the crack initiation and development. Sand particles exhibit inferior water-holding capacity compared to clay particles, leading to the preferential formation of cracks at the interfaces between sand particles and clay particles. (2) Incorporating sand into the clay matrix significantly suppresses crack development, with this effect strengthening as the sand content increases. The crack-suppressing efficacy of sand particles exhibits a first increasing then decreasing trend as the particle size increases, with an optimal particle size range (0.5 to 1.0 mm) determined under the experimental conditions. Furthermore, the crack-suppressing effect of sand particles amplifies with rising temperatures.