Abstract: On the basis of in-situ nitrogen generation system of sodium nitrite and ammonium chloride commonly used in oil fields, the effects of various factors on gas production performance were investigated by atmospheric pressure/high pressure gas production experiments. The results show that when the molar concentration ratio of reactants is 1:1, the higher the reactant concentration, hydrogen ion concentration and temperature, the higher the reaction rate and gas production. The initial pressure of the reaction has little effect on gas production of the system. The heat generation capacity of the in-situ nitrogen reaction increases with an increase in the concentration of reactants, the concentration of hydrogen ions, and the initial reaction temperature, and the peak temperature of the reaction system is also increased. The reaction kinetic equation of NaNO₂/NH₄Cl system is dc/dt=-7.103×10⁷c(H⁺)^{1.329 1}c₀^{2.094 9}e^(-51.28/RT). There are two intermediate products during the mixing reaction of NaNO₂ and NH₄Cl, i.e, H₂N-NO and HN=NOH. The reaction rate is determined by the reaction forming H₂N-NO by NH₃ and N₂O₃ through the nucleophilic substitution process of S_N2. The HN=NOH obtained by H₂N-NO conversion can be spontaneously decomposed, producing the final products N₂ and H₂O.