In this work, low-softening-temperature and low-modulus SiO₂ was introduced as an embedded interface between SiC nanowires (SiCnws) and the Ba_xSr_1−xAl₂Si₂O₈ ceramic matrix to enhance the strength and toughness of the ceramic. In the sintering process, molten SiO₂ enhances the flowability of the ceramic powders and modifies the dispersion of the SiCnws. The strengthening effect of SiCnws was fully realized, and the flexural strength of the optimized ceramics reaches 193±16 MPa, which represents an increase of 52.6%. After the formation of the embedded SiO₂ interface with a low modulus, cracks can deflect along the SiCnws surface, which is consistent with the criterion of He and Hutchinson. This can effectively extend the crack propagation path, and the fracture toughness is thus improved by 94.0%, reaching 3.1±0.5 MPa·m^1/2.