Vanadium was extracted from vanadium and chromium-bearing slag from the vanadium smelting process by air oxidation process and alkaline leaching process under atmospheric pressure. The effects of alkali concentration, leaching temperature, ratio of liquid to solid on the leaching rate of vanadium by orthogonal experiments were examined, and the leaching kinetics was also studied. The results showed that the optimum leaching conditions were the NaOH concentration of 100 g/L, leaching temperature 100℃, ratio of liquid to solid 4 mg/L and leaching time 1 h. Under the conditions, the leaching rate of vanadium reached 98%. Vanadium leaching process was in line with nuclear shrinkage model, the leaching process was controlled by diffusion step, and the apparent activation energy was 11.04 kJ/mol.