The invention relates to a high polymer used for controlling concrete cracks in building cement concrete engineering, effectively improving the toughness, impact resistance, bending resistance, bending resistance and impermeability of concrete, and inhibiting the cracking of the middle layer of asphalt roads and the generation of reflection cracks, etc. The production method of special-shaped plastic steel fiber. It uses polypropylene, polyethylene, polyester and other copolymers as the main raw materials, through advanced production technology and special treatment of fiber structure, to obtain rough surface, five-lobed, six-lobed and multi-lobed cross-section, and a cross-section of Concave-convex, wavy, zigzag shaped fibers. The fiber has high tensile strength, large elastic modulus, acid and alkali resistance, aging resistance, easy dispersion, light specific gravity, and firm combination with cement concrete and asphalt concrete.