Plant trichomes are special structures that originate from epidermal outgrowths. Trichomes play an important role in plant defense against pests and diseases, and possess economic and medicinal values. Study on molecular mechanism of plant trichomes will contribute to the molecular design breeding and genetic improvement of crops. In recent years, the regulation mechanism of trichome development has been basically clarified in the model plant Arabidopsis thaliana, while great progresses are also found in other plant species. In this review, we focus on the developmental regulation of trichome formation from gene and phytohormones levels in Arabidopsis and cotton (with unicellular trichomes), as well as in tomato and Artemisia annua (with multicellular trichomes). The research progress associated with trichomes is also introduced in other typical monocotyledons and dicotyledons. Finally, the research and application of plant trichomes are prospected.