Zinc films with three different thicknesses in the range of 1—3 μm were deposited on a glass substrate under a high magnetic field of 3 T, and compared with the samples prepared without magnetic field. It’s indicated that the all samples in 3 T magnetic field tend to align in the c-axis direction of zinc crystal and those prepared under in 0 T have lower intensity in c-axis with the thickness increasing, as shown by the X-ray diffraction results. From the scanning electron microscope photographs we found that crystals of zinc films prepared in 3 T magnetic field have refined appearance compared to the ones without magnetic field. Thermodynamic theory was used to analyze the coacervation of zinc aggregates. Preliminary analysis shows that the critical nucleation radius r*M and critical nucleation Gibbs free energy ΔG*M in the magnetic field is less than r* and ΔG* in normal state. Thereby, the nucleation intensity of zinc crystals in 3 T magnetic field is larger than that in 0 T and accordingly the refine ment phenomenon ensues.