The invention discloses a side slope surface guniting solidification protection method and relates to the technical field of construction. The method includes the steps: selection of pressure-free high-permeability grout, estimation of guniting amount, slope surface repair, preparation of pressure-free high-permeability grout, mounting of a guniting system, primary guniting, removal of slope surface laitance, secondary guniting and subsequent treatment. The pressure-free high-permeability grout has the advantages of high strength, high adhesion, low porosity, high water resistance, high acid resistance, high weather resistance, low shrinkage, normal-temperature solidification, simplicity in construction and long service life for engineering use. The pressure-free high-permeability grout is sprayed to sandy side slope surfaces to form solidified layers on the sandy side slope surfaces so as to realize a side slope solidification protection function. The side slope surface guniting solidification protection method has the advantages of convenience in construction and effectiveness in sand solidification and is applicable to protective reinforcement of sandy soil side slopes, weathering resistance of sandstone side slopes, reinforcement of loose gravel side slopes prone to slip, sand prevention and sand consolidation.