With the development of cities, habitat fragmentation has intensified and the risk of biological invasion has increased greatly in recent years. Invasive alien plants have invaded the ecosystems of urban green spaces, and some invasive alien plants have become dominant plants in some urban park habitats, gradually occupying the living space of native plants and seriously threatening the biodiversity of native plants. To contrast the distribution patterns of invasive alien plants in Beijing's parks, this study selected parks in four different functional areas (core area,expansion area,suburban area and distant suburban area) of Beijing for a sample survey of invasive alien plants, and explored the composition and distribution patterns of invasive alien plants in parks in different functional areas based on the sample survey data of 255 plots from 19 typical parks. A total of 40 invasive alien plant species were recorded in this study, belonging to 12 families and 29 genera, among them, Compositae was the dominant family, with the majority of annual herbs. Galinsoga parviflora and Erigeron canadensis had greater frequency and ecological niche width and were more widely distributed, while Bidens frondose and Amaranthus blitum had the greatest dominance and stronger resource competitivity. Invasive alien plants had the highest abundance in the parks of the expansion area and the lowest in those of the core area. The comparative analysis of the four districts showed that: 1) the Shannon-wiener index, species riches index and Pielou index of invasive plants in the parks of the expansion area were significantly higher than those of the core area and the outer suburbs (P<0.05). Simpson index of invasive plants in the outer suburbs was significantly higher than that in the expansion area and suburbs (P<0.05), while the opposite was true for native plants. 2) The invasion intensity index (III) of invasive plants in the parks of the expansion area was the highest and significantly higher than that of the core area (P=0.008), and there was no significant difference in other areas. 3) Results showed that the community composition of the core park was different from the other three areas, and the other three areas were all similar. Moreover, the abundance of invasive alien plants in Beijing's parks was positively correlated with the urbanization gradient in general, except for the core area. In conclusion, the plant communities in the core area parks had weak resistance to invasion, and the invasive alien plants in the parks of expansion area are rich, which are in a dominant position and need to be managed in time.