Abstract: Hydrogen diffusion coefficients of pure iron under different experiment conditions are obtained by electrochemical permeation double electrolysis cell method. The results indicate that material status, specimen thickness and permeation times have influences on hydrogen diffusion coefficient. Hydrogen diffusion coefficient of pure iron of the original state is higher than that of the three times quenching state. As the specimen thickness increases, the diffusion coefficient becomes higher. For the same position,the diffusion coefficeient of the secdonary hydrogen permeation is higher than that of the first hydrogen permeation.