Methane dry reforming (MDR) has attracted significant attention for effectively consuming greenhouse gases and producing valuable syngas. The development of coking- and sintering-resistant catalysts is still a challenge. Herein, highly active Ni nanocatalysts confined by the active edges of boron nitride have been originally developed, and the coking- and sintering-resistant MDR mechanism has also been unraveled. The active edges of boron nitride consisted of boundary BOx species interact with Ni nanoparticles (NPs), which can contribute to the activation of both CH4 and CO2. The etching of BN is restrained under the buffer of boundary BOx species. Operando spectra reveal that the formation and conversion of active bicarbonate species is accelerated by the boundary BOx species. The complete decomposition of CH4 is suppressed, and thus the coke formation is restricted. The functional groups of active BN edges are confirmed to stabilize the Ni NPs and facilitate the MDR reaction. This work provides a novel approach for the development of coking- and sintering-resistant catalysts for MDR.