Abstract—Inthispaper,asystemthatcanproducealterableand rotary permanent magnetic field is developed. It can be used for crystal growth, chemical crystal and biologic cell, etc. A homogeneous magnetic field can be produced in the central region by two annular permanent magnets, and the density of magnetic flux is controlledbychangingtheangleofthemagneticfieldproducedby the inner annular magnet and that produced by the outer annular magnet.Theanglecanvarycontinuouslyfrom0to180degree,consequently,causingthedensityofmagneticfluxvariedfrom0.006to 0.18Tesla.