This study first reports the synthesis of polyaniline (PANI)/multiwalled carbon nanotubes (MWNTs) nanocomposites carried out by the high gravity chemical oxidative polymerization (HGCOP) method in a rotating packed bed (RPB). The results show that the uniform core-shell tubular structure with diameters of 30-50 nm was successfully formed and PANT was covalently bonded to MWNTs. The conductivity of PANI/MWNTs prepared by RPB is higher than that by the stirred tank reactor (STR) when the content of MWNTs is lower, and the conductivities of the two nanocomposites get close with the increase of MWNTs content. This method provides a significant improvement to the rapid mixing method to prepare PANI/MWNTs nanocomposites in large scale. Moreover, it has potential applications in the synthesis of other polymer nano composites.