Taking literature[1] as theoretical basis, 99 pieces of inner or outer rings of 6202 deep groove ball bearing are randomly sampled respectively in production field. After information encoding, they are machined under conventional technological condition. The relative data are treated with computer, the characteristic parameters of harmonic distribution of each working operation are obtained, and the heredity, significance and stability of harmonic of each working operation are diagnosed and analyzed. According to centerless grinding circleforming theory and quasidynamic harmonic circleforming theory, measures of controlling weak working operation are adopted with the purpose of harmonic control.