The invention discloses a boiler system and an operation method for the same. The system includes a boiler, an induced draft fan, a desulfurizing tower, a condenser, a chimney, a first pipeline arranged between the induced draft fan and the desulfurizing tower, a second pipeline arranged between the condenser and the chimney and provided with a smoke exhaust valve, a first return air pipeline provided with a primary fan, a first air valve, a first cycle flue gas valve and a first oxygen injection valve, the first return air pipeline being connected to the second pipeline and communicating witha primary air port, and a second return air pipeline provided with a secondary fan, a second air valve, a second cycle flue gas valve and a second oxygen injection valve; the second return air pipeline is connected to the first and second pipelines and communicates with a secondary air port; and the smoke exhaust valve is located at the downstream of the first ends of the first and second returnair pipelines. According to the embodiments, the system has advantages of low operation costs and carbon dioxide emission, and safe and steady switching can be realized between air combustion conditions and oxygen-enriched combustion conditions.