Abstract: The effect of total oxygen content and nitrogen content on the quality of H type steel and the type and morphology of macroinclusions and microinclusions in steel were analyzed concerning the change of total oxygen content and nitrogen content during H type steel manufacturing in Jinxi Steel. Volume rate method was applied to calculate the distribution of various inclusions in steel. Inadequate primary deoxidization in liquid steel and high total oxygen in steel account for excessive inclusions. The undulation of inclusion quantity ac-counts for the formation of cracks. From tundish to billet, the elimination rate of inclusions is about 40%. The origin of most inclusions is not unitary. The granule diameter of micro inclusions in billet is small. Inclusions of 0~10 μm account for over 64%, while inclusions of over 20 μm do about 20%.