Abstract:PI-1 and PI-2 polyimide films were prepared from 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA) and ODA确良by two-step polymerization under the thermal and mixed imidization procedures. PLM showed that the PI-1 film was amorphous and PI-2 film had a similar "well" texture and the typical black cross extinction of the morphology of spherulite. The diameter of the spherulite was 0.02 mm to 0.03 mm. At the same time, from the phase diagram of AFM on PI-2 film，as chains in an regular arrangement, there were two parts of bright and shade, which proved that the existence of the a nonrandom structure. From WAXD, the order degree of PI-2 film was higher than that of PI-1 film. SAXD showed that, at 2θ= 3.115°, there was a small diffraction peak from the polyimide film, which is correspondent to a nonrandom samdwich with the layer spacing d=2.83 nm.The reason was that the PI segmers got from mixed imidization procedure form crystal nucleus which let the molecular chains regularly stack.