Cyanazine is widely used for weed control, but its residues may contaminate the soil environment. To reduce the harm of these residues, we investigated cyanazine adsorption and degradation in four typical Chinese soils. We also examined cyanazine degradation in relation to moisture, temperature, pH, organic matter, biochar, biogas slurry, biological bacterial fertilizer, microorganisms, and initial concentration. The degradation rates of cyanazine in the four soil types were as follows: yellow cinnamon > Phaeozem > Inceptisol > sandy loam. Additionally, the adsorption ability of the soils followed this order: Phaeozem > yellow cinnamon > Inceptisol > sandy loam. The degradation rate of cyanazine increased with higher temperatures (15–35ºC), soil moisture (15-80%), and decreasing soil pH. The half-life of cyanazine was approximately six times longer in sterilized compared to unsterilized soil (61.72 vs. 9.84 d). Adding a small amount of organic matter, biological bacterial fertilizer, biochar, or biogas slurry to the soil increased the cyanazine degradation rates. These results provide guidance for risk prevention with the use of cyanazine. These findings indicate that soil physicochemical parameters, especially pH, organic matter content, and temperature, should be considered in combination with the cyanazine application rate for achieving satisfactory weed control and reducing environmental risk associated with using cyanazine in different crops.