Abstract: A long-term monitoring of community structure and its dynamics of urban forests using the permanent plot-based approach may help reveal development direction and intrinsic mechanism of the forest community. A 1 hm² lot was set up in the Haiwan National Forest Park, Shanghai, in 2011. Survey was made of the plot and record kept of all the species of plants in the plot, particularly arbors taller than 1.3 m, for analysis of species composition, floristic elements, and vertical and horizontal structures of the community. Results show that a total of 73 species of vascular plants were recorded, belonging to 68 genera and 31 families.Of the 68 genera, 51.8% were of the temperate flora and 46.4% of the tropical one. Arbor individuals taller than 1.3 m reached 3,094, of which 1670 speciesindividuals were evergreen trees of 6 species, accounting for 48.0% in community importance, while the remaining 1424 individuals, deciduous trees of 7 species, accounting for 52.0% in importance. The six species, i.e. Ligustrum lucidum, Camptotheca acuminata, Photinia davidsoniae, Sapium sebiferum, Koelreuteria integrifoliola, Cinnamomum camphora, were in the top of the list in importance, forming a hierarchic structure, vertically. At a 0-50m scale, L. lucidum trees were distributed in groups, C. acuminata trees in an even-random-group pattern, P. davidsoniae and S. sebiferum trees in a group-random-even pattern, and K. integrifoliola and C. camphora trees in a random-group-random pattern. In terms of characteristics of population structure, the plot was a patch of evergreen and deciduous broad-leaved mixed forest dominated with north temperate and pantropic floristic elements, which characterized structure of the natural vegetation of the plot. The establishment of such long-term monitoring sample plots may provide data for following origin, development and succession of urban forests on urbanized plain area of the Yangtze River Delta.