Stray dog invasion caused by human activities poses a significant challenge to wildlife communities worldwide. Conservation biology efforts must prioritize controlling stray dog populations to maintain equilibrium within local wildlife communities. In the Helan Mountains, ungulate population recovery and the absence of top predators present critical issues. The presence of a stray dog as a predator may complicate ecological restoration efforts in the region. Through molecular and camera trapping data analyses, we investigated the overlap of ecological niches between stray dogs and local carnivores across nutritional and spatiotemporal dimensions. The results revealed a high overlap between stray dogs and local carnivores across various niches, likely linked to food abundance, suggesting the possibility of increased future competition between them. Stray dogs cannot be ignored when conservation of wild carnivores involved.