Novel exfoliated polyethylene (PE)/palygorskite nanocomposites prepared by in situ polymerization are characterized by solid-state nuclear magnetic resonance (NMR). The phase structure and molecular mobility are investigated by a combination of proton and carbon NMR. The results showed that incorporation of small amounts of palygorskite had great influence on the phase structure and molecular mobility. The incorporated palygorskite hindered the crystallization process and introduced motion-hindered chains in the NMR crystalline and amorphous phase. C-13 cross-polarization and magic-angle spinning NMR revealed two orthorhombic crystalline phase with different line-width. The chain mobility of orthorhombic crystalline phase with broad resonance line is obviously hindered compared with the phase with narrow resonance line when the filler is introduced. Additionally, the results of pulsed field gradient NMR technique show those the tortuosities in the nanocomposites are much higher than that in the bulk PE. The self-diffusion process of probe molecules is also influenced by the palygorksite load. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1363-1371, 2010