The data from NOAA/16 AMSU and the numerical prediction data from NCEP are used to study the thermal structure of tropical cyclones (TCs) occurred over the northwest Pacific Ocean during June 10—September 10 in 2002. The results show that various geophysical parameters of the different intensities of tropical cyclones can be detected sensitively and measured further by AMSU data. Therefore, some aspects of the warm core associated with these storms can be found. In addition, the substantial correlations between this satellite-depicted warm temperature anomaly at the mid-and upper-troposphere and surface pressure at the storm center can be found by the differences from height, magnitude, scale and form of temperature anomaly regions of the different intensity tropical cyclones at the target levels, the differences of height, size and distribution of negative temperature anomaly at upper troposphere and the structure characteristics of relevant humidity field. By the thermal structure of tropical cyclones, the intensity changes of tropical cyclones in the future and be acquired further. At the same time, the results show that for the temperature anomaly the magnitude, height and area of typhoon's warming is the most, and the strong tropical storm's follow it, while those of the tropical storm are the lowest. At far as the height of the negative temperature anomaly at the upper troposphere, typhoon is the topmost, the follow is strong tropical storm and the tropical storm is the lowest.