The invention discloses a global sea rainfall inversion method. The method comprises the steps that 1) a scattering factor threshold is set, a scattering factor SI is calculated, and whether a rainfall event occurs is determined according to the scattering factor threshold; 2) first-level sea data and TMPA 3B42 sea data are extracted, the first-level sea data matches the TMPA 3B42 sea data according to a sea matching rule, convection intensity CI of a cloud system is calculated, different inversion models are selected for different types of convection intensity CI for inversion, and a sea rainfall rate is obtained; and 3) results of the steps 1) and 2) are integrated to obtain a final sea rainfall rate. The sea rainfall inversion result obtained by the method is higher in accuracy, and canserve as reference for an FY-3C/MWHS-II sea rainfall service algorithm, and provides basis for subsequent researches of value weather forecast and data assimilation.