The invention relates to an on-line inner oil scraping device for a steel pipe, which comprises an oil scraping sleeve and a connecting rod, wherein the oil scraping sleeve is in the structure of a round table; moreover, the oil scraping sleeve is provided with a center inner hole, the outer diameter of the upper bottom surface of the oil scraping sleeve is smaller than the inner diameter of the steel pipe, and the outer diameter of the lower bottom surface of the oil scraping sleeve is greater than the inner diameter of the steel pipe; moreover, a deformation groove is annularly arranged on the lower bottom surface of the oil scraping sleeve; and the connecting rod comprises an installing section, an oil containing section and an oil scraping section which are sequentially arranged, wherein the installing section, the oil containing section and the oil scraping section are isolated by stop blocks, the connecting rod is arranged on the top by the installing section, the oil containing section has a certain length, and the oil scraping sleeve is sleeved on the oil scraping section by the center inner hole and is also fixed. Compared with the prior art, the on-line inner oil scraping device for the steel pipe has the characteristics of simple structure, convenience in manufacture and the like. According to the on-line inner oil scraping device for the steel pipe, the aim that the oil scraping operation of the inner wall of the steel pipe is carried out in an on-line way in the rolling process of the steel pipe can be realized, and the efficiency is high; moreover, the effect is favorable; the recycle rate of rolling oil is enhanced; and furthermore, the inner wall degreasing difficulty in the subsequent working procedure of degreasing of the steel pipe is effectively lowered.