A water-soluble chitosan derivative of N-(2-hydroxy)propyl-3-trimethylammonium chitosan chloride (HTCC), synthesized by the reaction of chitosan and glycidyltrimethyl ammonium chloride, and polyacrylonitrile (PAN) were blended using 46% (w/w) NaSCN aqueous solution as a common solvent. The total polymer concentration of blend solution was fixed at 12% (wAv), and the relative composition of PAN/HTCC in the blend solution varied from 0/100 to 80/20 by weight. The PAN/HTCC blend fibers with the appropriate physical property were prepared by a wet spinning and drawing process. The effect of HTCC content on the structural change, miscibility, and ability to be dyed of the blend fibers was investigated. The optical and scanning electron microscopic observation gave no indication of phase separation up to 20% HTCC content. Differential scanning calorimetry and dynamic mechanical measurements of the blend fibers show single glass transition temperatures that increase with increasing blend ratio of HTCC. All the experimental results exhibit that the blends are miscible on the molecular scale. The blend fibers could be dyed with an acid dye. This enhanced ability of the blend fibers to be dyed with acid dyes could be useful for one-step dyeing when mixed with other fibers, such as wool and nylon.