Abstract: Polypropylene/Ethylene-octene copolymer blends(PP/POE = 100/10)were prepared using a two-stage extruder with the aid of supercritical carbon dioxide(sc-CO2).The morphology of PP/POE blends was characterized by scanning electron microscope, and the size distribution of POE in PP based on SEM images was carried out quantitatively using a computerized image analyzer with Image-Pro Plus software. n differential scanning calorimeter was used to study the crystallization and melting behaviors of the samples，and the crystal morphology of PP/POE blends was observed by polarized optical microscopy equipped with a hot stage. The results showed that PP2. 5 sample, in which POE elastomer droplets were uniformly dispersed，had minimum average diameter(0. 34 μm) and size distribution(1. 44)of POE elastomer domains. PP2. 5 sample also had the highest degree of crystallinity (53. 57%)，and the smallest size of crystallites in all of the samples.