Abstract: During the micro-scale combustion experiment, it is necessary to measure the temperature of the whole combustion area to get the flame height data using thermocouple temperature measurement method. Due to the small micro-flame combustion area, the thermocouple may disturb the combustion stability. To solve the problem, digital image processing method is used to analyze flame image based on the linear relationship between image grey values and flame temperature to get the flame height data indirectly. Results show that the flame height data is accurate and agrees with the experiment result. This indirect measurement method for microflame is simple and feasible.