ZnSe nanocrystalline thin films were deposited on Si wafer using thermionic vacuum arc (TVA) method. For the first time, binary semiconductor thin films were deposited by TVA. The microstructure and surface morphology of the ZnSe nanocrystalline thin films were investigated using X-ray diffractometry, scanning electron microscopy, energy-dispersive X-ray spectrometry, and atomic force microscopy (AFM). Grain dimensions and grain size were determined by AFM measurement. Moreover, spectroscopic ellipsometer was used to characterize the refractive indices of ZnSe nanocrystalline thin film. According to experimental measurement, ZnSe nanocrystalline thin film was polycrystalline with (1 1 1), (2 2 0), and (3 1 1) preferred orientations. Refractive indices were approximately 2.50 in all visible ranges. Our results show that nanocrystalline thin films can be deposited with TVA method.