On June 2, 2016, during our survey on the breeding waterbirds colony at Pangong Lake in Ngari Prefecture, Tibet, we found two eggs of Bar-headed Geese (Anser indicus) were laid in an incubating nest of the Brown-headed Gulls (Larus brunnicephalus). It was speculated preliminarily of two reasons for this interspecific nest parasitism behavior. One might be the shortage of breeding nest sites and nest material resources for the geese and gulls in the smaller breeding island. The other might be that some nests and eggs of geese being predated, and the birds had no time to complete the next reproduction before the fall migration. We did not follow the fate of this nest. The diets of these two bird species were different, however, the precocial geese fledglings might not needed to be fed by Brown-headed Gulls, making it possible for this interspecific nest parasitism.