Using field observations and molecular analysis, we found a case of multiple brood parasitism in Xiaolongmen National Forest Park, Beijing, China, which the host was the Eastern Crowned Warbler (Phylloscopus coronatus), and the two parasitic eggs belonged to the Oriental Cuckoo (Cuculus optatus). This case belongs to Multiple Parasitism, which means one single host nest has two or more parasitic eggs that belong to one or more parasitic females. In this case, one nestling successfully hatched from the egg, others failed and the two eggs that out of nest were discovered by us. DNA was extracted from the tissue of the above two eggs and fresh blood which belong to parasitic nestling and one host. Portions of the cyt b gene were amplified via the polymerase chain reaction (PCR) and then the sequences had been compared with cyt b gene sequences in GenBank. The sequences suggested that both the young brood parasite and one egg that failed hatched belonged to the Oriental Cuckoo, the host and another egg belonged to the Oriental Cuckoo. What’s more, the young brood parasite had a pair of patches on palate also could prove it is Oriental Cuckoo. The morphology and molecular evidence were both demonstrated this case was multiple parasitism, and this study will contribute to more insight into brood parasitism.