The NCEP/NCAR globally tropospheric 1°×1° reanalysis data have been employed to select six landfall typhoon cases in order to diagnose variations of typhoon warm sectors in atmospheric boundary layer during their whole life periods.Results show that typhoons had different characters of boundary layer temperature and vorticity fields at different life stages,and the intensity of typhoons was inversely proportional to the distance between warm center and maximum positive vorticity center,that is to say,the smaller the distance,the stronger the typhoon.