Direct combustion experiments of asphalt mixture specimen to test the combustion time, surface temperature index for evaluation of the effect of flame retardant on flame retardancy of asphalt mixture were designed and conducted; Calculation method for smoke area in combustion to determine the smoke suppression of flame retardant was proposed. Road performance test of asphalt mixture to evaluate the effect of flame retardant on road performance of asphalt mixture was carried out. Test results show that the higher the use level of flame retardant, the higher the oxygen index of asphalt, the shorter the combustion time, the lower the surface temperature, the better the smoke suppression of asphalt mixture specimen. The addition of acidic flame retardants that have better flame retardancy significantly reduces the high temperature stability and water stability of asphalt mixture. The suitability to use flame retardants in the asphalt pavement project should be taken into account in terms of both flame retardancy and road performance of asphalt mixture.