Citric acid is a kind of organic acid widely existing in nature, which can affect the migration of radionuclides through complexation. The diffusion behavior of citric acid to Re(VII) in Na+- and Ca2+- bentonite with compacted densities of (1.40~1.80) g/cm3 was studied by through-diffusion method，the effective diffusion coefficient (De) and rock capacity factor (α) were obtained. The results showed that the De and α of Re(VII) diffused in Na+- and Ca2+- bentonite decreased with increasing density of compacted bentonite. Compared with Ca2+-bentonite, Re(VII) obtained from Na+-bentonite has a smaller diffusion coefficient and a larger adsorption distribution, indicating that Na+-bentonite has a better retarding performance. And the diffusion coefficient and adsorption distribution ratio(Kd) of Re(VII) in Na+-and Ca2+-bentonite increased after adding citric acid. The experimental results showed that the zero potential points of bentonites were all less than 7.0, indicating that the bentonite was electronegative and not easy to absorb Re(VII) in anion form. Adsorption experiments showed that the Kd of Na+-and Ca2+-bentonite to Re(VII) increased after adding citric acid, and as the concentration of citric acid increased. Through formula fitting, the De value and effective porosity (εacc) of Re (VII) diffused in bentonites fitted Archie's law very well, from which the cementation factors(n) obtained are 2.14 and 2.19, respectively. And their apparent diffusion coefficients (Da) are exponentially related to the compacted density of bentonite (ρ). All of them accord the rule of nuclide diffusion in clay.