Disclose are is method of manufacturing a ventilation sheet for a vehicle. The ventilation sheet for a vehicle is manufactured by performing anti-fouling finishing treatment using an anti-fouling coating agent including an anti-fouling composition. The anti-fouling properties can be improved to prevent the sheet from being fouled, and flame-retardant treatment is performed through a flame-retardant aqueous solution including flame-retardant PET fiber and flame retardant in bath so that the deterioration of flame retardancy caused by the improved anti-fouling properties can be prevented through the flame-retardant treatment while ventilation properties are maintained.