[Objective] To understand the characteristics of speciation and bioavailability of heavy metals (Cu, Cd, Pb, and Zn)in greenbelt surface (0-20 cm) soil within the 5th ring road of Beijing City in order to provide reliable information for soil heavy metal pollution control in Beijing City.[Methods] A total of 151 surface soil samples were collected from greenbelt land built 2~400 years ago. A modified BCR extraction technique was used to analyze the chemical forms of heavy metals from the collected samples. Risk assessment code (RAC) and the ratio of secondary phase and primary phase (RSP) were used to evaluate the bioavailability of the heavy metals.[Results] The average content of total Cu, Cd, Pb, and Zn in soil samples were 31.42, 0.29, 29.89 and 76.78 mg/kg, respectively. The content of total Cu and Zn were higher in the northeast and central region, Pb was higher in central region, and there were a few high-Cd areas existed in the northwest, northeast, and south region. The speciation distribution of Cu, Cd, Pb, and Zn were ranked as:residual > oxidizable > weak acid soluble > reducible, and the concentrations of stable heavy metals were much higher than available heavy metals. The bioavailability was ranked as:Cd > Zn > Cu > Pb. Risk assessment code (RAC) showed that Cd and Zn was at low environmental risk level, and Cu and Pb was no environmental risk. The ratio of secondary phase and primary phase (RSP) showed that the RSP values of Cu, Cd, Pb, and Zn was 0.06, 0.49, 0.18 and 0.13, respectively, most of the soil samples were not polluted by heavy metals.[Conclusion] The environmental risk and pollution of heavy metals (Cu, Cd, Pb, and Zn) of greenbelt soil within the 5th ring road of Beijing City are at a low level, but enough attentions need to be paid on heavy mental occurrence form.