To explicate how the grain shape of sand can influence its isotropic consolidation and shear characteristics, an isotropic consolidation test, a drained triaxial test and a cyclic undrained triaxial test had been carried out on materials whose particle size and grain size distribution are the same but grain shapes are different. From these tests it appeared that the shape differences have a great influenceon the angle of internal friction, the dilatancy characteristics, and the liquefaction resistance; and that the compression index when the sand is isotropically consolidated is uniquely determined by the initial void ratio, and the modulus of deformation indicating the rigidity in the early stage of the shearing by the volume decrease potential.