With the identification of ground photos taken by unmanned aerial vehicles （UAV） in urban areas， information on ground buildings can be quickly obtained. And the geomorphic conditions in the survey area can be effectively obtained and parameterized. The category of the near ground wind field in this area can be determined by establishing the corresponding relationship between the ground roughness Z0 and the growrd roughness index α. At the same time， the wind field and wind profile in the area were measured by the anemometers carried by UAV， and the near ground wind field category in the area was obtained through analysis. The near ground wind field categories obtained by the two methods are compared. The results show that the site categories determined by the two methods are consistent， and the relative error is within 5%. The research realizes the judgment of wind field category related to the target building according to the actual landform， and the method proposed in the paper has broad applicability. The research results can provide new ideas for the wind resistance design of buildings in urban areas.