Small amounts of organoclays of different sizes and concentrations were added into thermotropic liquid crystalline polymer (TLCP) forming four types of organoclay-modified TLCPs (TC3 white, TC3 dark, TC3 FS, and TC3 UP), which had different rheological behaviors in the nematic temperature region of TLCP. Acting as viscosity reduction agents, 1.0 wt% of each organoclay-modified TLCPs were blended with high molecular mass polyethylene (HMMPE), respectively. The organoclay-modified TLCP/HMMPE blends displayed different rheological properties from each other or compared with HMMPE and 1.0 wt% TLCP/HMMPE blend [PT1]. The organoclay-modified TLCPs had greater viscosity reduction efficiency than the original TLCP in HMMPE, a lower yielding stress and yielding start shear rate, and a narrower yielding transition region than those of PT1. The rheological performance of the blends, 1.0 wt% TC3 white/HMMPE, 1.0 wt% TC3 FS/HMMPE, and PT1, could be successfully described by a binary flow pattern model.