Nitrogen dissolving behavior in 304 stainless steel melts was researched in laboratory by bubbling nitrogen gas under different temperature and partial pressure of nitrogen. The results show that nitrogen solubility increases with increasing of nitrogen pressure and decreasing of temperature. Based on the thermodynamic and kinetic analysis, the calculation equations of nitriding thermodynamics and kinetics were established. compared with the experimental results in 304 stainless steel melts, the calculation results were in good agreement with the measured values.