Abstract: A series of progresses and breakthroughs in the theoretical model, structural design and preparation of field electron emission cold cathodes in recent 20 years were summarized. The theory of the band bending mechanism for field emission in wide-band gap semiconductors and the structural enhancement mechanism of field emission from multilayer semiconductor films were proposed, and it was confirmed in the experimental study of field emission characteristics of nano-semiconductor. Several kinds of field emission cold cathodes with excellent field emission properties were developed in the experiment, which laid a foundation for the practical application of new vacuum nano electronic devices. The bottleneck problems and future development trend in this field were proposed.