Through quick shear test of artificial soils and natural soft soils，the effects of mineral constituents for fine clay’s strength characteristics from micro perspective were studied. Studies show that: the shear strength and the index of single component samples are correlated with the surface properties of mineral particles and bound water properties. Clay minerals have larger specific surface area and cation exchange equivalent, the particle surface produce micro electric field strongly and the formation of thick viscosity bound water film, enhance the cohesive force between the particles which showed high cohesion, and the intergranular dislocation easily lead to lubrication friction which present the lower shear strength and internal friction angle; strength characteristics of artificial soils with mixed mineral composition and natural soil samples is micro factors’ comprehensive reflection, such as friction between the particles, cement agglomerated of different types of minerals and bound water properties. As long as some fine clay mineral content exceeds a certain limit, strength properties of mixed soil samples is determined by the fine particles of clay minerals.