Specific Polyaniline (PANI) morphologies such as nanotubes and nanofiber are required for enhancing its performance in the various applications. CO2 -assisted Polyaniline polymerization is a method recently used to produce these anticipated morphologies. In this study, polyaniline nanotube was prepared successfully in the presence of compressed CO2 utilizing Aniline as a monomer and Ammonium peroxydisulfate (APS) as an oxidizing agent. The effect of both reaction temperature and the oxidizing agent feed rate on the morphology and surface area of the produced PANI was investigated. The synthesized PANI was examined by FT-IR, XRD, and BET surface area analysis. Furthermore, SEM was carried out to figure out the morphology of the prepared PANI. It was indicated that Polyaniline nanotubes PANNTs size and homogeneity were affected by the reaction temperature. The averages of the outer and inner diameters of the PANNTs at 25 degrees C, 45 degrees C, 65 degrees C were found to be about (120, 60 nm), (140, 65 nm), and (175, 75 nm) respectively. Also, the produced surface area was slightly augmented with the increase of the temperature. In addition, it was observed that increasing the feeding rate of the APS was associated with the reduction of the size and the surface area of the produced PANI nanotubes.