The invention provides filter paper of an air filter of fuel conservation and a manufacture method thereof. The filter paper consists of base paper and a sizing agent which is coated on a single side or double sides of the base paper gram weight of between 110 and 160 gram/meter<2>, and water-base resin (butt) is 5 to 30 percent of mass of the base paper. The sizing agent comprises the following components in weight percentage: 2 to 20 percent of the water-base resin (butt), 1 to 20 percent of powder functional material, and 60 to 80 percent of water. The powder functional material is more than one of tourmaline ore powder with far infrared emitting property and releasing anion property, molten mass powder of rare-earth zirconium oxide and alumina, molten mass powder of rare-earth zirconium oxide, titanium oxide or rare-earth zirconium oxide, zinc oxide and the like. With the filter paper, fuel can be saved by 3 to 10 percent, but power of the engine is increased by 5 to 20 percent; noise of the engine is reduced by over 10 decibels, and exhaust emission pollutants are reduced by over 10 to 30 percent.