To investigate of the properties of coefficients of shear strength equation of compacted sand and gravel materials, the drained triaxial compression tests were performed using various mixtures of 9.50～2.00mm graveland 2.00～0.25mm sand. The following results are obtained.
1）There are tolerable correlations between dry density ρ_d or void ratio e and the fundamental coefficients φ, A or φ_m expressing of the relation between shear strength τ and normal stress σ.
2）There are no correlation between ρ_d or e and coefficients τ_0, b or a expressing of non-linearity ofτ and σ.
3）There are nearly linear relation between uniformity coefficient U_c and φ, A or φ_m, but there are no relation between U_c and τ_0, b or a.
From these results, it is considered that the properties of shear strength of sand and gravel materials are not esimated from grain size distnbution or dry density.