Through a solution and casting method, we successfully prepared poly(ethylene suberate) (PESub)/octavinylpolyhedral oligomeric silsesquioxanes (ovi-POSS) nanocomposites at low ovi-POSS loadings. Ovi-POSS dispersed homogeneously in PESub matrix, showing regular crystalline morphology. Both PESub and ovi-POSS crystallized separately in the nanocomposites. Ovi-POSS did not obviously affect the thermal stability of the nanocomposites. The influence of low ovi-POSS loadings on the crystallization kinetics and morphology of PESub was investigated in detail under different crystallization conditions. On the basis of the crystalline morphology study, the influence of low ovi-POSS loadings on the crystallization behavior of PESub was attributed to the different nucleation density values of PESub spherulites induced by ovi-POSS in the nanocomposites, which was further related to the influence of ovi-POSS loading on the dispersion of ovi-POSS in PESub matrix.