Focusing on basic structural characteristics of coal molecules, basic parameters of bituminous coal and anthracite including vitrinite reflectivity, industrial analysis and elemental analysis were analyzed in detail. The study of this chapter would provide an important basis for the subsequent chapters. At the same time, 13C Nuclear Magnetic Resonance spectroscopy (NMR) and Fourier Transform Infrared Spectroscopy (FT-IR) were employed to analyze the distribution of aromatic structure, fat structure and active functional groups in coal molecules in detail. Relative contents of different aromatic carbons in coal were determined, and ratios of aromatic bridge carbon to weekly carbon were calculated. Furthermore, structural characteristics of coal molecules were revealed. Moreover, aromatic structural units of coal molecules were characterized, which provided basic data support for the subsequent construction of coal spontaneous combustion active group model and the study of its weak interaction with extractants.