We clarified the saturated and unsaturated mechanical properties of typical soils distributed in Northeast Thailand. We sampled a soil with a yellow color (Yellow soil) as a typical soil. The mechanical properties of the Yellow soil were investigated by using oedometer, pressure plate and triaxial test apparatuses. The results of oedometer tests showed that yield stress increased as suction increased, the slopes of e - logσ_v (e: void ratio, σ_v: vertical stress) curves in the elastoplastic region were affected by the suction, and this soil expressed a large amount of volume reductions due to soaking of water. The results of the pressure plate tests showed that the air entry value was about 10kPa, and the volume change behavior due to suction was elastic when the suction value exceeded about 30kPa. The results of triaxial compression tests revealed that by comparing the specimens with the same confining pressures but different suction values, the higher suction the greater deviator stresses of specimens, the shear strength also increased with increasing suctions, however, the suction influence became weaker as the confining pressure increased.