Conjugated polymer crystals enable us to realize an ideal platform for the highest density-of-state of electrons in valence and conduction bands. Herein we report a facile protocol to prepare crystalline particles (P3HT-CP) of poly(3-hexylthiophene) (P3HT) with clear cubic shapes. Long-range ordering of P3HT has been confirmed by microscopic techniques, suggesting extremely small contribution from amorphous domains in the cubic structures. The comparable electronic absorption spectra of P3HT-CP dispersion and the thin-film of P3HT-CP suggest the suppression of additional structural evolution during solvent evaporation and stable dispersion.