The main problems existing in Beijing plain area are as follows:the landscape of uniform tree species is lack of vertical layer especially in ground cover plants,let alone pay attention to species diversity and density,as well as seasonal colors.There are few ground cover species in high canopy forests,and the phenomenon of understory blank is prominent.To enrich the diversity of ground cover plants under forests,10 cold resistant fern varieties were introduced to carry out adaptability research tests such as cold tolerance,negative tolerance and cold tolerance. Four varieties of fern,including Mexicans fern,Banas fern,Japanese color leaf fern and Ostrich fern,suitable for understory planting in Beijing Plain were selected.The evaluation indexes and methods of the adaptability of the introduction and cultivation of cold resistant fern were summarized. The screening and evaluation experiment of cold resistant fern enrich the species of ground cover plants,and provide more choices for high-quality landscape construction of the capital.