Suspension oxidation roasting is an efficient method for enhancing vanadium extraction from shale ore, however, the mechanism research of the process in extracting vanadium is not complete. In this work, vanadium extraction, kinetics, phase transformation, and microstructure evolution of vanadium-bearing shale during the suspension roasting process were systematically investigated. 900 °C was the optimum roasting temperature. The higher temperature caused materials sintering and hindered vanadium leaching. The mechanical function of the thermal decomposition process of vanadium shale was the nucleation model (A1/4): f(α) = 1/4(1 − α)[−ln(1 − α)]−3 and G(α) = [−ln(1 − α)]4; Eα = 243.7362 kJ/mol and As = 16.8559 s−1. According to the X-ray diffraction (XRD) analysis results, the lattice of main vanadium-bearing minerals, such as muscovite, kaolinite, and limonite, was destroyed at 900 °C. A better vanadium leaching efficiency could be obtained at this temperature. Meanwhile, the result of Scanning electron microscope (SEM) analysis indicated that the dense layered structure transformed into a loose porous structure after the roasting at 900 °C. However, material sintering occurred and it hindered vanadium leaching when the temperature was above 950 °C. The results of XRD and SEM explained the reason for vanadium leaching rate changes with roasting temperature.