[Purposes] This work aims to explore the suitable modified materials and repair process for the protection of earth sites. [Methods] The metakaolin and hydrated lime were added into the plain soil, the optimal ratios of two materials and its comprehensive engineering properties were obtained based on the laboratory tests, and further model experimental studies on their repair effects and process on disease in rammed earth walls were carried out. [Findings] 1) When the ratio of hydrated lime and calcium hydroxide is 1∶1 and the proportion of both materials in modified soil is 20%, the porosity of modified soil (HL-MK) are greatly reduced compared with that of plain soil, and the unconfined compressive strength of HL-MK modified soil is about 4 times of that of plain soil, the impermeability is 100 times higher, the bond strength is 1.2 times of that of plain soil, and the disintegration property is 1.2 times of that of plain soil. 2) Based on the model test of rammed earth wall with three types of disease such as partial collapse, surface erosion and cracks, the repair processes of laying adobe, spraying and slurry grouting repair method were proposed. After the repair of diseases in soil sites, the denudation rate, cracks propagation rate, temperature and humidity gradient are greatly reduced. [Conclusions] It can be seen from the above studies that the HL-MK modified soil and the repair process proposed in this paper can be applied to the restoration of soil site diseases, and can provide scientific reference for the restoration of soil site diseases in semi-arid areas.