Aiming to improve vanadium leaching rate and provide theoretical basis for vanadium leaching from low-vanadium steel slag through wet leaching, the whole leaching process was studied in dynamics and effects of temperature, liquid-solid ratio, leaching time and stirring velocity were observed. Results show that vanadium leaching rate from low-vanadium steel slag could reach to 98.8% at 90 °C when leaching in the solution with liquid-solid ratio of 10:1 and containing 4.0 mol/L hydrochloric acid and 8.0 mL hydrogen peroxide for 90 min. An empirical equation describing the leaching process was obtained from orthogonal experiment and dynamics derivation. The dynamical model of wet leaching vanadium from low-vanadium steel slag is the unreacted shrinking core model while the apparent activation energy of the leaching process is 7.21 kJ/mol. The model shows that control steps of the leaching process depend on the diffusion speed of the boundary layers. Vanadium leaching velocity could be sped up and the yield could be improved by enhancing temperature, liquid-solid ratio and leaching time.