A two-step processing was developed to prepare Yb2Si2O7-SiC nanocomposites. Yb2Si2O7-Yb2SiO5-SiC composites were first fabricated by a solid-state reaction/hot-pressing method. The composites were then annealed at 1250 degrees C in air for 2hours to activate the oxidation of SiC, which effectively transformed the Yb2SiO5 into Yb2Si2O7. The surface cracks purposely induced can be fully healed during the oxidation treatment. The treated composites have improved flexural strength compared to their pristine composites. The mechanism for crack healing and silicate transformation have been proposed and discussed in detail.