Applying an oscillating magnetic field perpendicularly on the high-quality magnetic fluid thin film, the phase separation of particles in the liquid matrix will occur. The concentrated phase makes up the cylindrical columns that can form two-dimensional lattices. The ordered structure of magnetic fluid thin films is the basis for the potential optical application. We explore the dynamical ordering formation of columnar lattices in magnetic fluid thin films subjected to oscillating perpendicular magnetic fields in this study. (C) 2004 American Institute of Physics.