As the composite of materials, fibers compositing, which can give full play to synergism of each fiber’s reinforcement, will become an inevitable trend. Calcium carbonate whisker is a kind of green environment-friendly fibrous powder filler with high strength, high modulus and excellent thermal stability, which has been proven that it has obviously toughening and reinforcing effects on cement-based materials. In this paper, CaCO3 whiskers composite with polypropylene fiber were added into concrete as reinforcement. Effect of different content of whiskers and fibers on the mechanical properties of concrete was investigated. The results shows that the composite of CaCO3 whisker and polypropylene fiber (PP) has better toughening and reinforcing effects than that of single filler. The strength of whiskers/PPF-reinforced concrete can be obviously improved compared with that of pure concrete, whisker concrete and PPF concrete. These increases could be correlated to the synergism of PPF and CaCO3 whisker, which are different in size, aspect ratio, elastic modulus, and reinforcing role in concrete.