Studied the reaction dynamics of the solution of N
2 in the liquid Fe-C-O system, measured the effect of partial preasure of N
2, content of O
2 and C, temperatures on the solution rate. This reaction was in first order when[O] content is lower; it was second order when[O] content is high; the rate of solution is lowest when the[O] content is very high. The influence[C] content on the mass transport constant of solution is evident. The apparent activation energy at first order is 131.6 kJ/mol, and 122.89 kJ/mol at second order.