A series of petroleum coke species obtained from commercial plants has been studied by polarized-light microscopy observation (PMO), scanning electron microscope (SEM), and Raman spectroscopy characterization (RS). The morphological characteristics of needle coke, shot coke, and transition coke differed apparently from each other. An explicitly close Growth/Sigmoidal relationship between parameters determined from polarizedlight micrographs and Raman spectra was observed. The full width at half maxima (FWHM) of D-1350 was more appropriate than I-D1350/I-G1580 for morphological correlation, and then establishing the criterion. It was shown that RS with proper spectra decomposition procedure could be a suitable and convenient method to quantitatively assess the morphology of petroleum cokes.