The environmental changes caused by urbanization were recognized as one of the main drivers for the decline in biodiversity. Butterflies, as an important component of biodiversity, play ecological roles and service values such as helping plants pollinate and supporting food chains, making them significant indicators of urban environmental changes. In this study, a combination of line-intercept and point sampling methods was used to investigate butterfly diversity in 47 urban green spaces within the fifth ring road of Beijing from April to September 2023. Then, the spatial pattern of butterfly species diversity and its relationship with environmental factors were analyzed. The results showed that: 1) A total of 4469 butterflies were surveyed, belonging to 5 families, 16 genera, and 17 species. Pieris rapae was the most dominant group, accounting for 74.67% of the total individuals, followed by Pontia edusa and Polygonia c-aureum. 2) Butterfly species diversity decreased with increasing urbanization. The species richness, abundance, and diversity indices of butterfly were highest in the outer of the city (between the fourth and fifth ring roads). There were significant differences in the Shannon-Wiener diversity index and Margalef richness index among different urban zones. 3) The result of non-metric multidimensional scaling (NMDS) showed that butterfly communities in different urban zones had high similarity. Further analysis of similarities (ANOSIM) showed that intergroup differences were small (R=-0.012, P > 0.05), indicating that the composition of butterfly species in urban green spaces was relatively similar. 4) The temporal dynamics of the three dominant butterfly species varied in different urban zones, especially the active period of Pieris rapae in the city center was earlier than in the city outer. 5) Redundancy analysis (RDA) results showed that butterfly species diversity was extremely significantly positively correlated with the total species number of plants in the study area (P < 0.001) and the species number of nectar plants (P < 0.001), and significantly positively correlated with urban green space area (P < 0.05). In summary, butterfly diversity tended to be homogenized in different urban zones, and urban green space area and plant diversity were important factors limiting butterfly species diversity. It was suggested that a certain proportion of urban green spaces should be preserved in urban area to expand butterfly living space. Moreover, increasing plant diversity and scientifically arranging different plant flowering sequences were recommended to provide more food sources for butterflies, so as to maintain or even increase butterfly species diversity.