Understanding water cycle is critical for our life. However, it has been difficult to estimate freshwater flux over the ocean by using ocean observation data because the number of in situ ocean observation data is extremely small and the distribution is inhomogeneous. On the other hand, satellite data are characterized by the high density, the high resolution and the homogeneity. Therefore, it can be considered that we obtain more accurate fresh water flux over the ocean by using satellite data. Recently we constructed surface latent heat flux data set mainly using satellite data. The data set is included in Japanese Ocean Flux data sets with Use of Remote sensing Observations (J-OFURO). Moreover, Tropical Rainfall Measuring Mission (TRMM) provides useful precipitation data in the tropical region. We can obtain fresh water flux data from above two data sets. First, we evaluate the TRMM precipitation data by using TRITON buoy data in this study. Second, we estimate freshwater flux over the tropical ocean and analyze the results.