Abstract: As the research about lift-off fire is the foundation of lift-off extinguishing against jet fire, the calculative method based on image parameters was proposed for studying the fire lift-off capability of perturbation flow surrounding flame. Firstly, the calculative method was explained. Then, the image acquisition and processing were introduced, and the mathematic model was established to calculate the lift-off distance, which represented the fire lift-off capability of the flow. Finally, the experiment was designed and the feasibility of the method was validated.