The invention provides a water feeding and oxygen adding process for a power station boiler, which is implemented by adopting the OT (Oxygen Treatment) technology and is suitable for a once-through furnace and a steam drum furnace. The oxygen adding step comprises a constant oxidization conversion step and a micro-oxygen running and film supplementing step; the constant oxidization conversion step is as follows: an outlet of a condensate polishing system and an inlet of a water feeding pump of a high-pressure water feeding system are subjected to oxygenation so as to oxidize the water feedingsystem, and the concentration of dissolved oxygen in main steam is controlled be smaller than or equal to 5mug/L; and the micro-oxygen running and film supplementing step is as follows: after an oxidization film is formed on the water feeding system, the oxygen adding amount of the high-pressure water feeding system is reduced, the added oxygen is only used for repairing and maintaining the oxidization film, and simultaneously, the concentration of the dissolved oxygen in the main steam is controlled to be smaller than or equal to 5mug/L. According to the process, a compact protective film formed and maintained on a metal surface of a pipeline of the water feeding system can be ensured, and the iron content of fed water can be reduced; the excessive oxygen can be prevented from entering ahigh-temperature heating surface so as to avoid the dropping of an oxide skin; and the oxygen consumption amount is lowered substantially, and the maintenance amount is reduced.