Abstract: Because of the complexity of reinforcing mechanism of reinforced ground,its design and theoretical researches fell far behind the engineering practice.According to the Prandtl’s assumption and analytical method of foundation,the principles of reinforced sand were analyzed,the approximate solution of bearing capacity for the single-layer reinforced sand was derived,and the relationship between length,depth of reinforcement and bearing capacity of reinforced sand was discussed.By contrast to the related model test of reinforced sand,the rationality of theoretical analysis were indicated.