The global expansion for massively introduced managed species has profoundly impacted biodiversity and ecosystem functions. However, it is unclear how introduced pollinators and mass-flowering crops simultaneously affect the structure and function of pollination networks. Here, we conducted field experiments to investigate the ecological impacts of introduced honey bee (Apis mellifera) during the flowering period of a mass-flowering crop (Brassica rapa var. oleifera) on plant-pollinator interaction networks and reproductive performance of wild plants in 48 alpine grasslands. We showed that the spillover of introduced honey bees had weak effects on the pollinator communities. In addition, honey bee spillover strengthened the pollination network structure’s stability and improved plant communities’ pollination function. These effects can be observed when the introduced honey bees and mass-flowering plants coexist in the alpine grasslands, highlighting the positive effects of honey bee spillover on the pollination-limitation alpine ecosystem.