Abstract: In order to improve the wetting property,PET fiber was treated on surface. Water-dynamic contact angles on the fibers were measured with the dynamic contact angle instrument. The roughness of the fiber surface was measured by AFM(Atomic Force Microscopy). The PET fibers treated and untreated were dyed with disperse dye,the sampling was done at spaced points in time,the chroma was measured with Datacolor SF600. Results show that the roughness of the fiber surface are increased after treatment,the contant angles are decreased,the dyeing speed is increased evidently,the process of dye may be shortened more than 10 minutes to achieve the same colors.