Abstract: An experimental project was undertaken to investigate the effect of temperature on initiation and propagation of desiccation cracks of clayey soil, and the computer image processing techniques and programming were applied to quantify the geometric structure and morphologic characteristics of surface crack networks after drying under different temperatures.The results show that the soil cracking generally experiences four stages of development which is significantly influenced by temperature. With increasing temperature, the crack patterns of soil samples tend to be simpler, and the crack width increases;Under lower temperature condition, the crack pattern is more complicated, the crack width is finer and the soil surface is more fractured; A new interpretation on the cracking mechanism is proposed based on double-layer theory of clay; An interesting phenomenon was discovered in the testing that most of the cracks intersect almost perpendicularly, and most of the polygons separated by cracks are quadrangular. The future research work on desiccation cracking is proposed.