The vacuum evaporation has been applied to prepare Zn and Bi films with different growth directions in order to investigate the orientation of films in magnetic fields. XRD results showed that magnetic orientation occurred in the Zn films with a smaller difference between magnetic susceptibilities of a-axis and c-axis compared with those of Bi in the magnetic field of 4T but the orientation did not take place in the Bi films prepared in a 5T magnetic field despite of a larger difference in magnetic susceptibilities. It was observed by SEM that the grain sizes in Zn and Bi films were markedly different. The relation between the grain size and the magnetic orientation was established in a magnetic field of 4T. The condition of orientation in films is that the magnetic energy should be 420 times larger than the thermal energy kT. The occurences of magnetic orientation growth in the films depends on the grain size of the film, the difference in magnetic susceptibility of the material and the intensity of the applied magnetic field, respectively.