Increasing urbanization worldwide resulted in increased human impacts on ecosystems. Urbanization effects on birds have drawn much attention from community to individual. At community level, urbanization impacts on assemblage, species richness, abundance, biomass, biodiversity, etc. were documented; Species level studies indicated the causes underlying bird community patterns in urbanization environment: different species have various responses to urbanization; Recent studies went further to detect urbanization pressures on birds by comparing individuals in behaviors and life history traits between urban environments and native habitats. Many evidences showed that a variety of factors induced with urbanization, including land use change, human disturbance, heat island effect, food change, nest predation, artificial light, etc. contributed more or less to the urbanization effects on birds.