International Society for Rock Mechanics（ISRM）proposed in 1995 a new type of rock fracture toughness specimen—cracked chevron notched Brazilian disc（CCNBD），however，the calibration of the dimensionless stress intensity factor，which is an important mechanical parameter for fracture toughness calculation，is still in question. In order to provide the flexibility for choosing the CCNBD specimen geometrical parameters in experiments，considering the geometrical restrictions suggested by ISRM，the new and more accurate wide range calibration values are obtained by using a new slice synthesis method combined with finite element analysis. The results of the slice synthesis method are proved to be more accurate and reliable than those counterpart methods presently available in the reference.