Abstract: A soil leaching column experiment was designed to investigate the release of cobalt from red soils under the impact by simulated acid rain.The results show that acid rain can accelerate the release of cobalt from red soils.Under the impact by simulated acid rain,there is a phase characteristic in the process of release of cobalt.But the phase characteristics of the release of cobalt are different among various soils.Under the experimental leaching intensity,the release of cobalt increases in the early phase and decreases in the later phase for 3 out of the 4 test red soils,while the release decreases in the early phase,increases in the medium phase and decreases in the later phase for the other test red soil.The impact of acid rain on the release of red soils can enhance the availability of cobalt in a short time,but in a long time it can lead to lack cobalt in red soils because of the mass losing of cobalt.