As an important component of urban ecosystem, urban parks and other nature reserves provide for the remaining birds with the habitats. However, the rapid urbanization causesnegative effects on the natural landscape and ecosystem, which leads to limited living space for birds as well as abnormal community structure. Taking the Nan-Haizi Milu Park for example with great urbanization in recent years, the wild birds' community structure and their species diversity are studied in the paper. The species, amounts and distribution of wild birds in Milu Park has been continuouslyinvestigated since October 2014. Till now, 18 orders, 49 families and 156 species of wild birds have been recorded in total, of which 16 species were ranked as the National Class II Key Protection Birds. The dominant species of birds varied with years and seasons. In general, the resident birds including Anas platyrhynchos, Cyanopica cyana, Passer montanus are dominant species in the study area. The Shannon Diversity Index and Pielou Uniformity Index of Birds in Nan-Haizi Milu Parkfollowed the sequence from high to low as 2018, 2017, 2016, and 2015 for the annualvariations and as autumn, summer, spring and winter for the seasonal fluctuation. Meanwhile, the influential factors on bird diversity were discussed. It was suggested that urban greenland should be connected to make it available for animals to pass through; the concept of landscape, forest, field, lake and grassshould be insisted to set up various landscape; human beings activities should be limited in wild life key protected sites; and habitats for wild birds should be watched and so on.