ABSTRACTFour types of spinnable pitches (MP‐N‐A, MP‐A, MP‐A‐H, and MP‐A‐N) for general‐purpose carbon fiber have been prepared under certain conditions with the refined pitch as the raw materials. Fourier transform infrared spectrum and solid‐state nuclear magnetic resonance spectra combined with curve‐fitting analysis have been used to characterize the average molecular structure (Iar, CH3/CH2, SAR, and SHFG) of spinnable pitches. Thermogravimetric analyses and polarizing microscope have been used to observe the thermal stability and the microstructure of spinnable pitches, respectively. The X‐ray diffraction combined with curve‐fitting analysis have showed that, the stacking heights (Lc) of these four kinds of spinnable pitches were 2.21, 1.78, 1.79, and 1.76 nm, respectively. The parallel layers (N) of each spinnable pitch were 7.30, 6.02, 6.06, and 5.97. What is more, the numbers of aromatic ring in each layer (n) were 17.03, 11.61, 11.75, and 11.41. Finally, the scanning electron microscopy has been used to characterize the surface morphology of carbon fibers which obtained by each spinnable pitches. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47880.