A fracture strength model applied at room temperature for the embedded crack was obtained based on the stress intensity factor model for embedded crack with an arbitrarily shaped front and Griffith fracture criterion. With further research on temperature effect on strength of ultra high temperature ceramics (UHTCs), a thermo‐damage strength model including the effects of temperature and crack shape was applied to each temperature phase. The fracture strengths were studied and analyzed. The conclusions were compared with the results obtained using the finite element software ABAQUS. This study will provide a theoretical basis and guidance on the design and preparation of the UHTCs.