The present invention discloses an immersion type rotating packed-bed reactor and an application thereof. A rotor filler is immersed in materials in the reactor; under the driving of the rotation of a rotor, the materials in the reactor form a loop; and when passing through the filler, the materials are fully sheared and dispersed into fluid micro-elements, so that the mass transfer rate and the reaction rate are increased. A feeding assembly simultaneously introduces materials of different phases to an inner edge of the rotor, a retaining ring and a baffle function to break a vortex, and a heat exchange assembly can maintain a system in a suitable temperature range. The present invention is suitable for heterogeneous systems such as a gas-liquid system and a liquid-liquid system. Compared with a conventional rotating packed bed, the material contact time is long, so that the reaction is more complete.