A high-modulus glass fiber composition, and a glass fiber and a composite material therefrom. The glass fiber composition comprises the following components in weight percentage: SiO2 55.7 to 58.9%, Al2O3 15 to 19.9%, Y2O3 0.1 to 4.3%, La2O3 less than or equal to 1.5%, CeO2 less than or equal to 1.2%, CaO 6 to 10%, MgO 9.05 to 9.95%, SrO less than or equal to 2%, Li2O+Na2O+K2O less than or equal to 0.99%, Li2O less than or equal to 0.65%, Fe2O3 less than 1%, TiO2 0.1 to 1.5%; wherein, the range of the weight percentage ratio C1=Y2O3/(Y2O3+La2O3+CeO2) is greater than 0.6. The composition can greatly improve the elastic modulus of glass, significantly reduce liquidus temperature and forming temperature of the glass, greatly reduce the crystallization rate of molten glass and bubble amount under the same conditions, and therefore is more suitable for large-scale tank furnace production of high-modulus fiberglass with low bubble amount.