The current work deals with the nonlinear vibration response of a porous functionally graded pre-twisted rotating blade with a square cutout at its center under thermal shock loading. The lower and upper surfaces of the functionally graded material (FGM) blade are composed of metal and ceramic, and the material properties that depend on the temperature at any point along the thickness are predicted as per the rule of mixture. The upper ceramic surface is exposed to sudden thermal shock, but the lower metallic surface is held constant at room temperature. The variation of the time-dependent nonlinear profile of temperature along the thickness is estimated using the Crank-Nicolson method. First-order shear deformation theory combined with Von Karman-type nonlinearity and an eight-noded element is used to build the finite element formulation for the present analysis. The total Lagrange formulation is used to deduce the governing differential equation for this analysis. The results derived from the current finite element method are matched with the benchmark example. The parametric study is carried out to investigate the effect of cutout size on the nonlinear vibration analysis of porous functionally graded pre-twisted rotating blades with square cutout under thermal shock loading. It is seen from the results that the cutout size has a pronounced effect on the nonlinear analysis.