The interface fracture of thermal barrier coatings (TBCs) can occur during the cooling following a thermal shock load. Previous studies indicated that multiple surface pre-cracks with a large density and short lengths reduce crack driving force at the interface crack. However, recent results from laser thermal shock tests showed that the coatings with very short pre-cracks were most vulnerable to the further surface cracking which in turn induced the interface crack. An analytical model was developed to predict the surface crack growth and the resulting interface crack driving force as a function of the pre-crack morphology. The results agreed with the laser tests and indicated that optimum pre-crack morphology can minimize the crack driving force at the interface.