In order to study the effect of pulsed laser nitriding on uranium, the crystal structure and oxidation kinetics of nitride layer were investigated using X-ray diffraction and in situ reactor chamber. The experimental results indicate that the crystal structure of nitride is affected by the scanning speed of pulsed laser remarkably. The UN is the sole nitride at lower scanning speed; the mix structure of UN and U₂N₃ will achieve at higher scanning speed. The oxidation kinetics of uranium is slow in the extreme when the surface is covered with a layer of UN. The oxidation kinetics and oxidation mechanism of nitride are analyzed and discussed in this paper.