The effect of RE elements in the liquid aluminum on growth kinetics of hot dip aluminizing layer of low-carbon steel was studied. The results show that the depth values of iron-aluminum intermetallic layer of the samples and its corresponded immersion time at 730 ℃ are substituted into the experience formula, adding small amounts of RE can increase the diffusion activation energy and decrease the diffusion coefficient of Al atoms, and therefore has effect on the increasing of growth rate of hot-dip aluminized coating. And the math formula was set up between depth values of iron-aluminum intermetallic layer of the samples and its corresponded immersion time. The effect of RE elements in the liquid aluminum on growth kinetics of hot dip aluminizing layer of low-carbon steel was studied. The results show that the depth values ​​of iron-aluminum intermetallic layer of the samples and its corresponded immersion time at 730 ° C are substituted into the experience formula, adding small amounts of RE can increase the diffusion activation energy and decrease the diffusion coefficient of Al atoms, and therefore has effect on the increasing of growth rate of hot-dip aluminized coating. And the math formula was set up between depth values ​​of iron-aluminum intermetallic layer of the samples and its corresponded immersion time.