The fuzzing and pilling of untreated, chlorinated and oxidized wool knitted fabrics were compared with frictional coefficients measured by capstan method, surface modification observed by scanning electron microscopy (SEM), the surface roughness and the scale height assessed by atomic force microscopy (AFM), and hairiness imaged on the three-dimensional rotational microscopy. The pilling comparative experiments of the corresponding knitted fabrics were conducted by means of Pillbox method. Experimental results showed that some scales on the oxidized fiber surface were partially cleaved and some grooves generated. With oxidization treatment, the anti- and with-scale of friction coefficient increase with decreasing the thickness of scales and the yarn hairiness. There is good correlation between the result of AFM and the change in frictional coefficients. The pilling grade of knitted fabric comprised of oxidization wool is 2.5, and the average numbers of pills per 25 $cm^2$ is 25. It is postulated that the surface topography, the frictional properties of oxidized wool fibers and surface hairs of corresponding yarns may limit the ability of those surface fibers to form fuzz and of those fuzz for pill formation.