[Objective] The construction and mechanical model of soil-concrete composite slope protection technology were analyzed in order to provide scientific reference for the implementation of slope modification engineering in soil-rock mountain area. [Methods] Using a slope damage mechanism based on the basic principles of geotechnics, we proposed the slope stability design concept of "retaining soil with soil". We used this basic design concept, combined with construction experiments to establish a stability calculation mechanics model of "soil-concrete composite", and also provided design suggestions for medium-high slopes. [Results] After nearly six years of construction experiments and operation, the rationality of the slope stability design concept of "retaining soil with soil" was verified. The two scientific models of "soil-concrete composite" (i.e., critical equilibrium state and ultimate equilibrium state) and their supporting formulas were also verified. Compared with traditional stone slopes, the "soil-concrete composite" slope protection technology could save more than 80% of the materials used in construction, and could accelerate construction speed by more than five times, with the initial construction cost being no higher than the cost of the stone slope. [Conclusion] Soil-concrete composite slope protection can replace the traditional stone bank slope protection, thereby effectively alleviating the conflict between slow construction speed and schedule requirements, as well as the conflict between the large amount of stone material needed for construction and the environmental protection aspects of quarrying. The soil-concrete composite slope protection technology has broad application prospects in the future.