Zinc bearing montmorillonite（Zn*Ca-MMT＆Zn*Na-MMT） were produced by zinc cation exchange reaction.X-ray diffraction analysis showed that the（001） basal spacing of montmorillonite crystal lattice increased after zinc cation exchange.This indicated that Zn2+ entered into the interlayer position of MMT as a hydrated cation or composite cation.The results obtained from antimicrobial trial in vitro indicated that MMT（Ca-MMT＆Na-MMT） has no antibacterial activity.Zn-MMT has strong antibacterial ability on the E.coli K88,and the antibacterial activity of the latter better than former.