In order to study the influence of different clay content on the fissure property of red clay, four kinds of samples with water content were prepared, and the fissure development laws of the samples were observed at 20 ℃ and 60 ℃ respectively. The fissure area, fissure rate and fissure length were measured and calculated by Image J image processing software, and the correlation analysis between the water loss process and the fissure process was carried out. The results show that when the water content is the same, the water loss rate from start to stop of development of fissure area and fissure length of red clay with the same clay content increases with the increase of temperature. When the water loss temperature is the same, the start-stop water loss rate of the development of fissure area and fissure length of red clay with the same clay content first decreases and then increases with the increase of initial water content. When the temperature and water content is same, the surface shrinkage of red clay gradually decreases with the increase of clay content. There was no obvious correlation between the change of clay content and the water loss rate from the beginning to the end of the development of crack area and length.