In order to investigate the law of spontaneous combustion in the integrated afterburner, taking the fuel injection system in the integrated strut as a research object and adopting the spontaneous combustion flame of the fuel under the condition of high temperature inflow recorded by high-speed photography, the effects of input temperature, inlet velocity, residual gas coefficient and fuel nozzle type on the spontaneous combustion properties of the integrated afterburner are investigated.The results show that the increment of afterburner inlet temperature makes spontaneous combustion easy, and spontaneous combustion can occur under all conditions when the inlet temperature exceeds 1200 K. The increment of afterburner flow velocity is advantageous to the suppression of spontaneous combustion, making the spontaneous combustion delay distance of fuel increase. In the case of lean oil, fuel particles can absorb more heat from the environment, and the delay distance of spontaneous combustion is reduced. Conical atomizing nozzles with good atomization effect are prone to spontaneous combustion, while direct atomizing nozzles with poor atomization effect are relatively stab. The research results provide a preliminary reference value for the design of oil supply system and ignition system of integrated afterburner.