The indoor drying-wetting cycle tests of composite clayey soil with different concentrations of organic polymer were carried out. By recording the change of water content of the sample and obtaining the characteristic pictures of crack development, the influence of the change of polymer concentration and the number of drying-wetting cycles on the moisture change and desiccation cracking of clayey soil was studied. The results show that: (1) the drying and water loss process of clay can be divided into three stages, and the internal water loss mainly occurs in the constant rate evaporation stage. Because the elastic membrane formed by the reaction of curing agent and water will block the "hydrophobic channel" in the soil, the water holding capacity of the soil will be gradually improved with the increase of the concentration of the polymer, and the time of constant rate evaporation stage was prolonged to some extent. (2) With the increase of the number of drying-wetting cycles, the cracks on the surface of the samples will be "healed" in different degrees. However, with the increase of the concentration of polymer, the soil particles are wrapped and cemented by elastic membrane, and the surface crack morphology of the samples changes little, and the overall stability is improved.