Halloysite nanotubes (HNTs) were used to prepare polypropylene (PP) nanocomposites through a novel vane mixer. The effects of melt blend time and halloysite content on properties of composites were investigated. SEM analysis was performed to show that HNTs were well dispersed in PP matrix with the increase of mixing time. DSC showed both the degree of crystallinity and crystallization temperature increased due to the introduction of HNTs into PP, which indicating a potential nucleation effect induced by the nanotubes. TGA illustrated that the presence of HNTs had two opposite effects on the thermal behavior. A surface catalytic action of the halloysite speeded up thermal degradation of PP. However, this effect was reduced with improved HNTs dispersion. Rheological investigations revealed that rheological properties were significantly increased by the addition of low fraction of halloysite to PP. The 2 wt% HNTs nanocomposites reached maximum tensile strength because HNTs dispersed evenly in PP.