Supercritical(SC) CO2 anti-solvent induced polymer epitaxy(SAIPE) method was used to help prepare nanohybrid carbon nanotubes(CNTs) wrapped with polyvinyl alcohol(PVA) nanocrystals. With the variation of a series of experimental conditions or peripheral effects, such as PVA concentration, CNTs concentration, and SC CO2 pressure, the optimal experimental variables for PVA-nanocrystals growing on CNTs have been found. The adsorption of polymer on CNTs via multiple weak molecular interactions has been studied by Fourier transform infrared(FTIR) spectroscopy and Raman spectroscopy. The mechanism about the formation of PVA nanocrystals on CNTs can be suggested through the experimental phenomena. These CNTs wrapped with PVA nanocrystals can be directly used as nanofillers to fabricate PVA composite fibers reinforced with CNTs by electrospinning.