Precipitation is a key process in the global energy and water cycle. It is more difficult to accurately measure real-time rainfall of ocean than that of land. The remote sensing data are essential for studying ocean precipitation in global energy and water cycle. In this study, based on the observed rainfall data at 6 climatological stations of island or coastal region during 1998-2012, the performance of 3B42 and 3B43 products of TRMM(Tropical Rainfall Measuring Mission) Version 7 has been assessed over the Bohai Sea. The spatio-temporal characteristics of precipitation in the Bohai Sea have been investigated based on the TRMM data at annual, seasonal and monthly scales. The results showed that at a daily scale, daily precipitation from the 3B42 product of TRMM and at gauge stations was weakly correlated, while at annual and monthly scales, both 3B42 and 3B43 products of TRMM well captured the spatial pattern and temporal variations of precipitation and the 3B43 product had comparatively better performance. In general, the TRMM products slightly underestimated rainfall over the Bohai Sea, especially obvious when the monthly observed rainfall was greater than 300 mm. For the period from1998 to 2012, precipitation over the Bohai Sea showed an inter-annual wet and dry fluctuation with annual mean rainfall of about 631.6 mm. The summer rainfall accounted for 62.0% of the annual rainfall and the maximum average monthly precipitation occurred in July. Spatially, rainfall in the Bohai Sea was higher in the central-south part and lower in the inshore regions. Influenced by atmospheric circulation, the gravity centers of rainfall over the Bohai Sea leaned toward the north-west in summer and toward the east-south in winter.