To improve the physical properties of polyacrylonitrile(PAU), the blends of PAH and poly(vinylpyrrolidone-g-acrylonitrile) (PGA) were prepared and were investigated by IR. X-ray difrractometer. Rheovibron, and Instron. PAH homopolymer and poly (vinylpyrrolidone-g- acrylonitrile) (PGA) were synthesized by suspension polymerization. These two constituents of the reactor blends were simultaneously obtained by incorporation of acrylonitrile into a little PVP backbone. Some interaction between PAN and PCA copolymer was identified, which was regarded as a dipolar interaction between the nitrile groups and the pyrrolidone carbonyl groups. All PGA were located in amorphous region of the blends. The phase structure of the blends was found to have correlation with contained quantity of PGA. The blend containing below 2 mol% of PVP had a uniform amorphous phase in which PGA was well dispersed in PAH matrix. Therefore tensile strength and elongation were increased. However, in the blend containing 10 mol% of PVP. a separated domain of PGA forms in the amorphous phase.