For accurate analysis of oxygen below 10ppm in steel, application of oxygen compound reagents is investigated in the inert gas fusion method instead of ordinary standard steel samples.Oxygen to the reagents can completely be extracted by using a Sn plus Cu bath and a good linearity is obtained in the calibration curve.In order to confirm the recovery of oxygen in highly clean steels, standard steel samples were analyzed by employing the calibration curve derived from reagents. Without metal bath, oxygen in steels was not perfectly recovered, while the application of metal bath (Sr or Sn plus Cu) resulted in complete extraction. These results show that proper regents are applicable for the calibration and use of suitable metal bath is needed for the accurate determination of oxygen in steel, especially for the low level below 10ppm.