A thermostable formula comprises the following components in percentage by mass: 1% to 5% raffinose, 5% to 10% maltose, 15% to 30% saccharose, 1% to 5% lactose, 1% to 5% glucose, 0.1% to 1.5% polysorbate 80, 0.1% to 0.5% polyethylene glycol 8000, 0.5% to 3% tyrosine, 3% to 6% silk fibroin, and the balance of water for injection. It further discloses a room-temperature-preserved live classical swine fever vaccine and a preparation method thereof, wherein the live classical swine fever vaccine is obtained by mixing the thermostable formula with a live classical swine fever virus solution and then carrying out gradient vacuum drying. The vaccine prepared according to the present invention has a dried foam appearance and presents a glass-layer like structure under a scanning electron microscope, has a glass transition temperature up to more than 50° C.
