The invention discloses a glass fiber capable of being used as an advanced reinforced substrate of a composite material, comprising the following components in percentage by weight: 57 to 65 percent of SiO2, 14 to 20 percent of Al2O3, 8 to 13 percent of CaO, 7 to 12 percent of MgO, less than 23 percent of CaO and MgO, 0.05 to 2 percent of Na2O and K2O, and 0.05 to 1 percent of Fe2O3. While the mold temperature, the liquidus temperature and the refining temperature of the glass fiber are maintained to be relatively low, through optimization and combination of the components, the mechanical performance of the glass fiber is greatly improved compared with conventional E glass fiber, and the increase range of monofilament strength can be increased up to 26 percent, and the total cost of the glass fiber is possibly close to or lower than the cost of the conventional E glass fiber, thus being easy for implementing large-scale industrial production.