A fast fluidized-bed reactor, device and method for preparing propylene and C4 hydrocarbons from oxygen-containing compounds. The device includes the fast fluidized-bed reactor and a fluidized-bed regenerator for regenerating a catalyst. The method includes: a) feeding a raw material containing the oxygen-containing compounds from reactor feed distributors to a dense phase zone of the fast fluidized-bed reactor, and contacting the raw material with a catalyst, to generate a stream containing target product and a spent catalyst containing carbon; b) sending the stream into a product separation system, obtaining propylene, C4 hydrocarbons, light fractions and the like after separation, returning 70 wt. % or more of the light fractions to the dense phase zone of the fast fluidized-bed reactor from the reactor feed distributor.