Abstract: The crystalline morphology of two kinds of nucleating agent- 1.3,2.4-di (p-methoxybenzylidene) sorbitol (DOS) and 1.3,2.4-dibenzylidene sorbitol (DBS) was studied. The new-synthesised nucleator-DOS effect on Isotactic polypropylene(IPP)crystaline morphology was also investigated. The SEM micrograph of DBS showed that the formation of DBS dulling rings was due to the connected cracks of DBS lamellae. Both DOS and DBS formed negative spherulites similar to those of IPP/DOS had a notable effect on the IPP surface crystals. There were spherulites formed on pure IPP film and the pebbled crystals were formed on IPP surface with the addition of a small amount of DOS. Compared with DBS, less amount of DOS was used and better transparency could be obtained.