Abstract: Hydroxyl terminated poly(silyl ether)s were synthesized from hydroquinone and tetramethyldihydrodisiloxane, which then reacted with aniline and polyformaldehyde to prepare benzoxazines with Si—O—C bonds. Structure of the products was confirmed by Fourier transform infrared spectroscopy and the proton nuclear magnetic resonance, repectively. Water contact angle test indicated that the obtained polybenzoxazine was hydrophobic. TGA results showed that the introduction of silicone improved the thermal stability of polybenzoxazine. Dissolution experiments demonstrated that Si—O—C bonds imparted chemical degradability to polybenzoxazine. The resins completely degraded within 24 hours in an acidic solution, generating phenolic Mannich bridge derivatives, hydroquinone and organosilicon oligomers. Glass fiber reinforced composites were prepared using these benzoxazines as matrix, and the maximum interlayer shear strength reached 18.93 MPa. The resin matrix completely degraded within 9 days in acidic solution while no resin was observed on glass fiber surface as examined by the scanning electron microscopy, achieving complete separation between resin and fiber reinforcement in composites. This work provides a novel strategy for designing recyclable high-performance thermosetting resin and composites.