The observation on the fracture morphology for the composites such as,glass fiber reinforced nylon 1010,carbon fiber reinforced nylon 1010,and EPDM-rubber toughened nylon 6, and the discussion on the factors influencing fracture of the materials show that the adhesion and distribution of the toughening and reinforcing agents with resin matrix directly affect on the mechanical properties of the material,and the changes in the mechanical properties are obviously reflected in fracture morphology.