We developed a new polymer-blending technique using high-shear flow field, and succeeded in making polymer blends with nano-dispersion structures. Using this technique, we have succeeded in blending various polymer blends without any additives, which have been very hard to mix with each other at the nano-level until now, and have prepared blends with a domain size of ten to several tens of nanometers is homogeneously dispersed densely in the matrix. In addition, such technique is also very effective for the nanofiller dispersions in polymer matrix.