In　this　work,　the　numerical　manifold　method　(NMM)　is　further　exploited　to　study　the　fracture　behavior　of　two-dimensional　functionally　graded　materials　(FGMs)　subjected　to　thermo-mechanical　loadings.　For　this　purpose,　the　steady-state　heat　conduction　simulation　of　the　cracked　FGMs　is　firstly　performed,　and　then　the　computed　temperatures　are　input　into　the　thermoelastic　modeling　to　acquire　the　mechanical　fields　and　the　fracture　parameters.　The　major　difficulty　of　the　problem,　i.e.,　the　representation　of　the　discontinuities　or　singularities　of　thermal　and　mechanical　fields　(e.g.,　the　temperature,　heat　fluxes,　displacements　and　stresses)　around　cracks　is　cleared　via　bi-cover　systems　of　the　NMM.　By　means　of　the　domain-independent　interaction　integral,　the　thermal　stress　intensity　factors　(TSIFs)　are　obtained.　To　verify　the　proposed　method,　four　numerical　cases　with　raising　complexity　are　tackled　on　mathematical　covers　inconsistent　with　all　physical　boundaries.　The　nice　agreement　between　our　results　and　the　existing　ones　well　demonstrates　the　superiority　of　the　NMM.　Besides,　the　effects　of　the　material　gradients　and　crack　configurations　on　the　TSIFs　are　also　inspected.