Abstract: To obtain the change rule of permeability of water repellent soil, the water-repellent clays with different levels of water repellent were obtained modifed by stearic acid. On this basis, the permeability tests under different initial water content, stearic acid content and compaction times were carried out by using a constant pressure permeameter. The changes of seepage duration and stable hydraulic conductivity of water-repellent clay were analyzed. The results indicate the content of stearic acid and the compaction times are important factors affecting the water repellency of water repellent clay. The stable hydraulic conductivity is positively correlated with stearic acid content and initial water content, and negatively correlated with compaction times. The stable hydraulic conductivity of clay modified by stearic acid was decreased from 10⁻⁴ cm/s to 10⁻⁵ cm/s, which means its impermeability was significantly improved. The results of variance analysis shown that the initial water content, stearic acid content and compaction times all had significant effects on the stable water conductivity of the sample, and the coefficients of determination of the model was 0.979. The range analysis results shown that the effect of the influencing factors on the stable water conductivity was: initial water content > compaction times > stearic acid content. The worst level combination of modified clay was water content 0%, stearic acid content 1%, compaction times 28 times, and the best level combination was water content 15%, stearic acid content 2.5%, compaction times 16 times. The results can provide reference for the application of relevant anti-seepage engineering.