The present work is aimed to investigate the effect of notch root radius. and angle psi of specimen on the critical effective T-stress. A notched plate made of molybdenum alloy TZM is considered and subjected to a tensile loading. In brittle materials, the tools derived from linear elastic fracture mechanics are applicable and the analysis was made according to a local approach defined by the volumetric method. Different values of notch root radius (rho = 0.5, 1, 1.5, 2 mm) and angle (psi = 0 degrees, 15 degrees, 30 degrees and 45 degrees) have been selected to conduct an analysis of the critical effective T-stress and the distribution of T-stress at the notch tip in brittle fracture. The effective T-stress T-eff has been estimated as the average value of the T-stress distribution in the region ahead of the notch tip at the effective distance X-eff. The obtained results showed that the variation of radius affects strongly the critical effective T-stress, while the variation of angle gives a very small change in values of critical effective T-stress.