Disclosed are a vacuum pouring device for steel ingots without tundishes and a pouring method of the vacuum pouring device. The vacuum pouring device comprises a vacuum pouring tank, a refined steel ladle body is arranged on the upper portion of a cover plate of the vacuum pouring tank, a sealing flange is disposed between the refined steel ladle body and the vacuum pouring tank, a sliding mechanism used for controlling opening states of nozzles of the refined steel ladle body and the quantity of injected flow is arranged in the sealing flange, an inlet end on the sliding mechanism is aligned with the center of the upper nozzle of a steel ladle and connected with the upper nozzle of the steel ladle, an outlet end of the sliding mechanism is connected with the lower nozzle, the lower nozzle is coaxial with a flow limiter disposed on the cover plate of the vacuum pouring tank, a slide plate blowing system and a nozzle bowing system are further arranged in the sliding mechanism, and a blowing pipeline penetrates through the sealing flange to be connected with an external gas source. Harmful gas can be completely prevented from entering liquid steel when the liquid steel in the refine steel ladle is poured into a tundish by the aid of the device, the device is simple and convenient in operation, and multiple times of discontinued pouring operation can be realized.