In this paper, by using the CFD open-source tool OpenFOAM, the wind speed distribution in the pedestrian zone is studied for the building wind environment with different building surface mesh sizes and different mesh types according to the relevant green building standards. It is found that under different building surface sizes, the area ratio of high and low wind speed is higher than middle wind speed between snap and no snap mesh. The area ratio of medium wind speed is higher than the others between snap and no snap mesh. Therefore, it is recommended to use a snap mesh type to simulate the outdoor wind environment of the building.