Abstract: This article suggests a "filmprogressive model" for inorganic ion exchange in sea water,whose features are simplicity and ease of mathematical treatment.It has a good straight line relationship when experimental data are plotted into graphs and there is a quantitative relationship between it and B.A.M theory and its formulae.Using this mudel and mathematical equations it has been decided that the rate of ion exchange of uranium (Ⅵ) and hydrous titanium oxide and/or Aluminium-Activated Carbon composite exchanger throughout the whole process is controlled by film-diffusion.Experiments prove "film progressive model" is correct under conditions of minor components and in sea water.It is at Least as effective as B.A.M theory.This model will exhibit its theoretical guiding effect in the comprehensive utilization of marine resources,in marine pollution and prevention,in marine geochemistry of elements and suchlike spheres in so far as the study of kinetical problems are concerned.