The invention discloses a system for oxidizing roasting-reducing roasting of titaniferous iron concentrate and a roasting process. A fluidized bed oxidation reactor is adopted for the oxidizing roasting of the titaniferous iron concentrate; the oxidized titaniferous iron concentrate enters a fluidized bed reduction reactor for reducing roasting; the reduced titaniferous iron concentrate is sequentially and spirally cooled by a cyclone cooler and water cooling and then enters a downstream section; and reduced coal gas is firstly subjected to heat exchange by the cyclone cooler, then preheated by a coal gas preheater, and enters a reducing furnace, latent heat of unreacted reducing gas in tail gas exhausted from the fluidized bed reduction reactor is firstly released through combustion in a combustion chamber, and hot flue gas generated by the combustion is mixed with the tail gas exhausted by the fluidized bed oxidation reactor and then enters a multi-stage cyclone preheater to exchange heat with the titaniferous iron concentrate for heat recovery. The system disclosed by the invention has the advantages of high reaction efficiency, full heat utilization, good economical efficiency in the roasting process and the like, and is suitable for large-scale continuous industrial production.