The relationship between dynamic damage and life activity of Bacillus subtilis was studied. The results showed: (1) Submicroscopic structure damage caused by dynamic actions could make the bacteria lose life. (2) Lower dynamic actions could make the Bacillus subtilis completely-break and its submicroscopic structure fatally damage. (3) The effects of micro-hole valve of homogenizer on bacteria's surface structure showed cell wall friction damage and cell membrane breakage. (4) The whole- breakage of bacteri...