The kinetics of stripping of thorium(IV) and uranium(IV) from tributylphosphate (TBP)-kerosene with dilute nitic acid solution has been studied using the Lewis cell technique. The effects of concentrations of Th(IV), U(IV), nitric acid, TBP, temperature and stirring speed on the stripping rate have been examined. The result show that the stripping rates of Th(IV) and U(IV) are all controlled by diffusion process.