The high-pressure crystallized poly (ethylene terephthalate) / bisphenol-A polycarbonate (PET/BAPC) blend samples were investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Besides the extended-chain single crystals with high quality and large c-axis thickness, the results showed that some novel crystal morphologies were formed in the multi-phase system within a relative short time. Spherulitic structures with different characteristics were observed, in and out the cultured polyester extended-chain crystals, respectively, and their substructures were found to be extended-chain lamellae. Furthermore, bud-like nano-crystals with zero- or one-dimensional structures, some of which aggregated and then evolved into three-dimensional nano-dendrites, were grown during the cooling process of the polyester blends at high pressure. The disclosed entities during this study may promote the understanding of formation process and mechanism for both spherulite and extended-chain crystals of polyesters, so as to instruct the processing of such alloyed engineering plastics with high performance.