The invention discloses a device for making steel by liquid casting through an induction furnace and electroslag. The device comprises the induction furnace, a vacuum degassing furnace and an electroslag liquid casting furnace which are sequentially arranged, wherein the vacuum degassing furnace is provided with a suction tube and a liquid feeding pipe; the suction tube is inserted into the induction furnace; the liquid feeding pipe is inserted into the electroslag liquid casting furnace; and the liquid level height in the electroslag liquid casting furnace is lower than the liquid level height of the induction furnace. The invention further discloses a steelmaking method. Liquid steel in the induction furnace is protected and cast into the electroslag liquid casting furnace by adopting the siphon phenomenon. The device and the method disclosed by the invention have the advantages of high safety coefficient, small occupied area of a workshop, high production efficiency, low productionand investment cost, excellent product quality and the like.