[Background] Bacterial diversity plays an important role in the ecological function of green space soil. However, there is no report on the soil bacterial diversity of urban parks at different age. [Objective] In order to study soil bacterial community diversity and structure characters. [Methods] Illumina Miseq sequencing was adopted to analyze soil bacterial community structures of typical old and young urban parks in Beijing. [Results] The results showed that 45 known phylum were found, among them, Acidobacteria, Proteobacteria, Chloroflexi and Actinobacteria were dominant bacterial groups in all soil samples. Alpha diversity analysis showed that there was a significant differentiation on soil bacterial diversity. The richness and diversity of soil bacterial community in old parks were higher than that of young parks. In addition, similarities analysis and principle coordinate analysis indicated that there was a significant differentiation in bacterial community structure between old and young parks. The redundancy analysis of soil microbial community structure and environmental factors showed that soil moisture, soil organic matter and total nitrogen were the key determinants influencing the soil microbial community structure, whereas none of the soil properties was found responsible for the changes in the soil bacterial community structure. [Conclusion] This study introduced the park age as an influencing factor for redundancy analysis. The results showed that park age is an important factor affecting the diversity of the bacterial communities in the urban parks.