The invention discloses a semi-closed type full-coverage separation method used for weathering protection of inscriptions on precipices and slopes. The semi-closed type full-coverage separation method is composed of a grid type framework, a double-support-plate bilaterally adjustable support base, a unilaterally adjustable support base, a single-support-plate bilaterally adjustable support base, transparent cover plates and a watering and cooling device. The lower ends of the double-support-plate bilaterally adjustable support base, the unilaterally adjustable support base and the single-support-plate bilaterally adjustable support base are fixed on the grid type framework; through the height adjustment of the support bases, the inclination angle of each transparent cover plate and a gap between adjacent cover plates can be changed. The transparent cover plates are assembled and paved along the slope surface of the inscriptions on precipices from downside to upside, and the adjacent cover plates which incline along the slope surface are paved in an imbricate manner. In order to avoid too high temperature of stones caused by sunlight exposure, the watering and cooling device can be turned on to enable the water to flow through the surfaces of the transparent cover plates from upside to downside and cool as well as clean the cover plates. The semi-closed type full-coverage separation method used for weathering protection of inscriptions on precipices and slopes achieves the advantages of obvious long-term effect, strong reversibility, installation convenience, easy maintenance, relatively low cost, no obstruction to tourism and view, and the like.