The most popular method to estimate intensity of tropical cyclones is the Dvorak technique (Dvorak, 1975, 1984). This paper is to improve tropical cyclone intensity estimation method by adding the TRMM data into the current method. One of the disadvantages of the Dvorak method is that the method is not based on a "physical parameter", like rainfall, moisture or wind speed. To complement such weak points additional methods to estimate intensity of tropical cyclones will be needed. We are now developing an objective method to estimate intensity of tropical cyclones using microwave data, such as TRMM PR/TMI data. At first, we are now preparing a database to extract characteristic features in TMI brightness tempreture data for estimating intensity of tropical cyclones. We use the best-track data and the QuikSCAT data of ocean surface wind as the reference of intensity.