Herein we demonstrate crystallization-driven self-assembly of isotactic polystyrene(i PS) with high isotacticity and narrow molecular weight distribution and crystallization-induced switching of the morphology of i PS aggregates in N, N-dimethylformamide(DMF). The formation and morphology switching of the self-assembled aggregates of i PS are investigated by means of dynamic light scattering(DLS), scanning electron microscopy(SEM), differential scanning calorimetry(DSC) and wide angle X-ray diffraction(WXRD). The results reveal that cooling DMF solution of i PS promotes i PS chains to self-assemble into spherical aggregates with a gelled core cross-linked by microcrystals, which is surrounded by solvent-swollen corona. Furthermore, crystallization induces the deformation of i PS aggregates from spherical to plate-like or nest-like. Herein we demonstrates crystallization-driven self-assembly of isotactic polystyrene (i PS) with high isotacticity and narrow molecular weight distribution and crystallization-induced switching of the morphology of i PS aggregates in N, N-dimethylformamide (DMF). The formation and morphology switching of the self-assembled aggregates of i PS are investigated by means of dynamic light scattering (DLS), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and wide angle X-ray diffraction cooling DMF solution of i PS promotes i PS chains to self-assemble into spherical aggregates with a gelled core cross-linked by microcrystals, which is surrounded by solvent-swollen corona. Furthermore, the crystallization induces the deformation of i PS aggregates from spherical to plate -like or nest-like.