This paper presents a probabilistic approach for predicting fatigue life of glass subjected to near‐ΔTC(critical temperature difference) thermal shock which exhibits little subcritical crack extension. First, thermal shock fatigue life Nf was derived as a function of temperature difference ΔT, fracture probability F and Biot's modulus β from the slow crack growth concept in conjunction with the Weibull distribution model. Next, thermal shock fatigue tests as well as flexural tests were performed for borosilicate glass to measure ΔTC and Nf versus ΔT. The parameters associated with slow crack growth were then determined from the experimental results while the heat transfer coefficient h or β was obtained with the aid of finite element analysis. Thirdly, the thermal shock fatigue diagram (ΔT−Nf curves) was depicted for various values of β. Finally, crack length was simulated on the basis of the present approach.