Magnetic fluid is a new kind of nanometer function material

which possesses magnetic character and fluid character. Magnet can levitate among the magnetic fluid

just like staying in vacuum with zero gravity. The new type sensor

base on the levitation character

can avoid the direct mechanical contact

and reduce mechanical friction.The magnetic-current couple effect and the interface effect between the fluid and solid are very evident in the suspension-type magnetic fluid inertia sensor. Base on the classical hydrodynamic theory

the kinematic viscosity equation obtained by fitting experimental data can be solved by associating with the fluid equation

when magnetic fluid can be considered as nonpolar fluid. The key factors to optimize the configuration of the sensor are to increase magnetic-current damp and to reduce the displacement of the magnetic body. The methods of step modeling and setting up integral variable in different field are used to analyze the theory equation

and numeric analysis researches are done on the magnetic-current damp of the objects with different structure. Numerical calculation and experimental result indicate that the viscosity of magnetic fluid

which can be controlled by magnetic density

makes much effect on magnetic-current damp. The structure with grooves can increase the magnetic-current damp and reduce the displacement by compensating the loss of the damp

when it reduce the differential pressure between the sides.