Glass general idea of the people as hard and brittle objects, not suitable as structural timber but if its wire, then its strength greatly increased and soft, so with the resin and shape after finally can become a good structural timber. It can be seen that the strength of glass fiber increases with its diameter. As a reinforcing material glass fiber has the following characteristics, these characteristics make glass fiber use far more widely than other types of fiber, the development speed is also ahead of its characteristics listed as follows: (1) tensile strength is high, elongation small (3%). (2) high elasticity coefficient and good rigidity. (3) The elongation in the elastic limit is large and the tensile strength is high, so the energy of absorbing shock is great. (4) For inorganic fiber, with non-flammable, chemical resistance is preferred. (5) Small water absorption. (6) The scale of stability, heat resistance is good. (7) Good processing, can be made into strands, bundles, felt, weaving and other forms of products. (8) transparent through the light. (9) The development of surface treatment agent with good resin quality is completed. (10) The price is cheap.