Abstract: Urban road green space is an important component of the urban green space system. The road greenbelt bears an important function in improving the ecological environment of the urban road. The cross section layout of the road greenbelt is the core of road green space planning and design. For the first time, ENVI-met is applied in the simulation of urban road section greenbelt planning and design, for quantitative study on the reduction of PM2.5 by the form of urban road greenbelt. The results show that: 1) the greening type of road cross section has a significant effect on the distribution of PM2.5. The road greening results in an increase in PM2.5 concentration in motorized lanes and a decrease in PM2.5 concentration in non-motorized lanes and sidewalks. 2) Road greening can significantly reduce the PM2.5 concentration of sidewalks. In terms of the area reduction of PM2.5, four-plate & five-greenbelt>two-plate & three-greenbelt>one-plate & two-greenbelt>three-plate & four-greenbelt. From the extent of PM2.5 reduction, two-plate & three-greenbelt>four-plate & five-greenbelt>one-plate & two-greenbelt>three-plate & four-greenbelt. 3) The best effect of reduction is achieved with the two-plate & three-greenbelt and four-plate & five-greenbelt greening, with up to 18% reduction in the sidewalks. This paper has confirmed that road greening can improve particulate pollution in non-motorized lanes and sidewalks, providing a strong support for reducing PM2.5 concentration with green infrastructure.