Poly(p-oxybenzoyl) (POB) whisker was prepared by polymerization of p-acetoxy-benzoic acid in the liquid paraffine at 33$0^{circ}C$ for 6 hours. Three types of POB whisker were prepared by the solution polymerization with different agitating speed. Polypropylene (PP)/POB whisker composites were prepared by mixing PP and POB whisker by using Brabender plusticorder at 22$0^{circ}C$. Thermal and viscoelastic properties of PP/POB whisker composites were investigated by using differential scanning calorimetry (DU) and Rheovibron. For the PP/POB whisker composites, the crystallization temperature of PP was shifted to lower temperature. Tan5 maximum peaks of composites were shifted to lower temperature as volume fraction of POB whisker increased.and the increase of spinning speed and melt flow rate. It was found that the tenacity decreased with the increase of FAR. After drawing (draw ratio=3.2), the FAR of drawn fiber in creased compared with the FAR of undrawn fiber.