The high-pressure crystallized poly(ethylene terephthalate) samples were investigated with scanning electron microscopy. The striation appearance, which is the most common feature of polymer extended-chain crystals, was clearly observed. Poly(ethylene terephthalate) extended-chain crystals with thickness np to 17 m were obtained at high pressure. Fibrous crystals were also formed at high pressure. The fracture behaviors, which affected the exposure of the striations, were also discussed.