Abstract: The dynamic contact angle analytical method of sisal fiber based on Wihelmy plate principle was developed on the basis of the quantification of the cross-section area by using Weibull statistical distribution function and the measurment of liquid wicking quality caused by the hollow structure of sisal fiber. On this basis, the influences of different surface treatment methods on the surface microstructure, the surface chemical composition, the surface energy as well as its dispersion, polar component were analyzed. Also the wettability between sisal fiber and E51 epoxy resin was measured. The results show that the surface polar functional groups and polar component of surface energy of sisal fiber are significantly increased after being treated by NaOH and flame retardants. Although the surface polar functional groups are increased by silane treatment, the polar component decreased with the total surface energy slightly reduced. The wettability between sisal fiber and E51 resin is closely related to the matching characteristics of polar ratio of surface energies.