The invention discloses a continuous vacuum induction melting sheet-casting furnace, a rare-earth permanent magnetic alloy cast sheet and a manufacturing method thereof. The continuous vacuum induction melting sheet-casting furnace mainly comprises a vacuum melting chamber, a side door, a cooling chamber, a vacuum isolation valve, a medium-frequency induction smelting device, a melting and turningmechanism, a tundish component, a rotary water cooling roller and a cooling roller, wherein the vacuum isolation valve is arranged between the vacuum melting chamber and the cooling chamber; the melting and turning mechanism is connected with the side door and is capable of moving along with the side door; the cooling roller is arranged in the cooling chamber and is mainly a cylinder structure with an opening in the front end. When casting, alloy molten liquid which is molten in a crucible of the medium-frequency induction smelting device is cast on the rotary water cooling roller which is rotating to form an alloy cast sheet; the alloy cast sheet is immediately thrown into the rotary cooling roller and is continuously cooled. The equipment and the alloy cast sheet manufacturing method can be used for manufacturing the rare-earth permanent magnet alloy cast sheet and rapidly-quenched neodymium-iron-boron permanent magnetic powder.