Nature has inspired mankind to create novel inventions with biomimetic structures and materials, where plants provide a significant source of inspiration. Plants have evolved a range of effective appendages, among which trichomes have attracted extensive research interest due to their enormous functions. It is important to understand trichome functions and corresponding mechanisms for their bioinspired applications. In this review, we provide a comprehensive overview of the diverse functions of trichomes, with emphasis placed upon their roles as biophysical barriers that can create a complex three-dimensional (3D) network to help the plant adapt to severe environments. Moreover, we also summarize the bioinspired applications of four typical trichomes, including needle-like, hook-like, foliar-like, and antenna-like trichomes. This review offers a new perspective of interdisciplinary research on both trichome functions and their biomimetic applications.