AN style="FONT-FAMILY: ’Times New Roman’; FONT-SIZE: 14pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang=EN-US>In this paper, the authors study the stress-field of minor earthquakes on the boundaries of hemas-microsoft-com:office:smarttags" />Henan, Shandong and Hebei provinces and make analyses on its dynamic evolution. The authors further discuss the relation between anomaly stress field and other physical parameters (medium earthquake evolution and velocity ratio anomaly) which reflect earthquake-generating laws. On this basis, the authors comprehensively determine the medium-strong earthquake preparation situation of the region.