Urban foresters are addressing the challenges of urban biodiversity loss through management plans to adapt to urbanization. Protecting the integrity of the urban ecosystem requires long-term monitoring and planning for resilience as well as effective management. Urban parks are important parts of the urban ecosystem and hot spots of urban biodiversity, with rich soundscape resources. Due to the informative, low-cost, and low-impact features, soundscape-related researches and applications have a great potential of monitoring ecosystem health. Acoustic indices have been commonly used in soundscape ecology researches to measure biodiversity conditions by summarizing the activity or diversity of biological sounds. In this study, we recorded the soundscapes of 20 city parks within Beijing urban area in spring, trying to describe the characteristics and changes of soundscape quantificationally. A total of 23,040 minutes of sound materials were automatically sampled from raw data using Python. Then we calculated three widely used acoustic indices (BIO, ADI, NDSI) that have been proven to be related to biodiversity. The soundscape intensity index, power spectral density (PSD), was calculated to measure acoustic features along every frequency interval. All the indices' calculation is based on R studio. Spearman rho correlation analysis and principal component analysis were carried out to explore how environmental vegetation structures affecting soundscape in park habitats. The results show that (1) acoustic indices can not only effectively characterize the soundscape information of urban parks, but also have significantly time-dynamic characteristics, which can accurately reflect important biological activities and ecological processes such as bird dawn chorus. (2) The acoustic intensity index also reflects significantly temporal variations and changes along the frequency intervals. Different frequency interval groups reflect the corresponding activity information of acoustic communities. These results also provide more supports to the acoustic niche hypothesis (ANH) theory. (3) Our PCA modelling results show that the vegetation structure, especially the vertical structure, plays an important role in urban soundscapes. More vertical heterogeneity or multilayered vegetation, is associated with more acoustic diversity in urban parks. In the absence of historical soundscape data, we systematically collected and analyzed the soundscape of urban parks in Beijing. This is a pilot study for soundscape in Beijing urban parks. Our findings support soundscape as a measurement of habitat vegetation status and emphasize its great potential for urban management and sustainable development in biodiversity and ecosystem monitoring, which will enable regular assessment of urban parks and forests to inform adaptive planning and management strategies.