The invention discloses a suspended-bed oil hydrogenating device and application thereof; the suspended-bed oil hydrogenating device comprises: a storage tank; at least one suspended-bed reactor including a shell and a barrel and arranged in mutual series, with at least one hydrogen access port arranged at the outside of the shell, wherein a connection pipe is arranged between the hydrogen access ports and an outlet end of a hydrogen storage tank; the upper and lower ends of the shell are provided with a discharge port and a feed port respectively; the feed port is communicated with an outlet end of an oil storage tank; the barrel is communicated with the feed port, a thermocouple element is arranged between inner and outer walls of the barrel, the outside of the barrel is provided with a plurality of outer holes, an inner sleeve is arranged in the barrel and is provided with inner holes communicated with the outer holes, the upper end of the barrel is provided with a stirring device, and the barrel is coaxially connected with the stirring device; a diversion pipe is arranged at the feed port of the suspended-bed reactor and is composed of a plurality of round pipes vertically arranged; a separation unit; a recycling unit. The suspended-bed oil hydrogenating device makes effective and maximum use of resources, and ensures conversion rate and quality of light oils at the premise of saving cost.