In order to study the treatment plan for collapsed sandy soil in sandpit embankments，the reinforcement method of rye grass root system was applied，and the influence of soil depth and root morphology characteristics on permeability level and bearing mechanics was analyzed. The results show that soil depth and root surface area do not affect the functional relationship between root soil permeability coefficient and static water confining pressure. The greater the depth of the soil layer，the more significant the inhibitory effect of static water confining pressure on the permeability coefficient of the sample，but the root surface area has the opposite effect on this. After the depth of the soil layer exceeds 24cm，there is a stress drop segment on the stress-strain curve of the specimen. Under the effect of increasing confining pressure，the peak stress of the specimen is more affected by the depth of the soil layer. Under confining pressures of 200 kPa and 400 kPa，the increase in peak stress of the specimen is 39.4 kPa and 65.8 kPa，respectively. The influence of confining pressure on the stress-strain curve characteristics of the specimen is greater than that of the root surface area. As the root surface area increases，the load-bearing capacity of the sample improves，but the growth effect slows down after the root surface area exceeds 30cm2. The paper has some reference value for the ecological management of collapsible sandy soil of embankments.