Sr₂MgMoO_6−δ (SMM) is one of promising anode materials for direct internal reforming solid oxide fuel cells as its excellent performance has been demonstrated. However, it is necessary to be chemically compatible with the electrolyte material to realize the original performance. In this study, we investigate chemical compatibility between SMM and typical electrolyte materials (8% mol Y₂O₃–92% mol ZrO₂; YSZ, 10% mol Sc₂O₃–1% mol CeO₂–89% mol ZrO₂; ScSZ, La_0.9Sr_0.1Ga_0.8Mg_0.2O_3−δ; LSGM) and anode interlayer materials (Gd_0.1Ce_0.9O_2−δ; GDC, Ce_0.8La_0.2O_2−δ; LDC) under conditions for preparing SMM electrode and operation. SMM formed a reaction layer with all of the typical electrolyte materials studied. LDC was the only material for the interlayer that maintains chemical compatibility with SMM, though it forms the reaction layer with YSZ and ScSZ. From these results, this study clarifies that LSGM and LDC should be used as electrolyte and interlayer, respectively, when SMM is used as the anode.