MCF is one of the intelligent magnetic responsive fluids developed. It is compounded by magnetic fluid (MF) and magneto-rheological fluid (MRP). The MCF is defined by the suspensions conducted from micro to nano ordered metal particles in MF, and is responsive to a magnetic field. Since the particles aggregate in the fluid by the application of the magnetic field, the fluid become to involve many magnetic clusters. By the effect of the existence of the clusters in the fluid, the properties of viscosity, magnetism and magnetic pressure change according to the kinds of the particles and solvent, and the fraction of the particles. The cause can be explained by the magnetic cluster model.