Abstract: The toughness, strength and rigidity of composites can be improved simultaneously by filling plerosphere particles into PP. The effect mechanism for improving the mechanical properties of the polymer filled with plerospheres was studied using the energy dissipation theory. And the method of a in situ observation under the tensile test with SEM was adopted to analyze the dynamic energy dissipation process of the crack generation, propagation and termination in the plerosphere/PP composite. The results show that the particles trigger massive cracks effectively and absorb energy, however, duly terminate the cracks propagation to prevent the deadly crack, which leads to the toughening and strengthening of the polymer. The results of the in situ observation and analysis to the dynamic process supply an effective test evidence for the energy dissipation mechanism in the plerosphere/polymer composite.