Urban allergenic pollen is one of the emerging and increasingly severe urban ecological problems associated with the process of urban ecological construction. To address this issue, it is important to identify the locations and flowering periods of highly allergenic plants and assess the potential exposure risk of their pollen to urban residents. This can help individuals with pollen allergies plan their schedules and outdoor activities more effectively. The study focuses on the highly urbanized area within the fifth ring road of Beijing and uses the densely distributed, high-pollen-producing pine and cypress trees as a typical case, mainly introduced through human planting. By exploring their spatial distribution and pollen release timing, we aim to reveal the spatiotemporal patterns of allergic risks and highlight the relationship between urban spatial patterns and the planting of allergenic vegetation. In addition, the study investigates the response and adaptation strategies of allergenic plants to urban environmental changes, highlighting their resilience and survival intelligence in urban environments. The results show that: 1) There are significant differences in the distribution of allergenic vegetation in cities based on urban development and different functional areas. In areas with higher urbanization levels, the planting of pine and cypress trees is relatively scarce. Residential areas, educational and cultural zones, historical and cultural heritage protection areas such as Sijiqing subdistrict, Haidian subdistrict and Tiantan subdistrict have high densities of pine and cypress trees, while agricultural and industrial zones such as Laozhuangzi subdistrict and Huangcun subdistrict have low densities of these trees. 2) The differences in flowering periods of urban allergenic plants demonstrate the diversity of plant responses and adaptations to the urban environment. Plants may begin to bloom early in 2019—2022, strategies that aid allergenic plants in survival and reproduction in urban environment. 3) Potential exposure risk of allergenic pollen change as plants adapt to the urban environment. Most streets in urban areas are classified as low-risk (93 subdistricts), followed by medium-low-risk areas (15 subdistricts), medium-high-risk areas (5 subdistricts), and a few high-risk areas (4 subdistricts) and moderate-risk areas (1 subdistrict). By analyzing the spatial distribution patterns and phenological characteristics of typical allergenic plants can couple urban green space exposure with public health, this study provides scientific evidence for optimizing urban greening construction and alleviating allergic pollen-related issues, and empirical references for future urban green space planning and construction.