Abstract: Different concentrations of sodium silicate were sprayed on ginger leaves at seedling stage.Its results show that appropriate concentration of silicon reduces malondialdehyde(MDA)content and relative electric conductivity(REC) which protects cell membrane integrality.On the other hand,excessive silicon increases the content of MDA and REC.Detail analysis show that sodium silicate treatment increases the activities of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT)and phenyllamine ammonialyase(PAL) to varying degrees.The effects of the first treatment are remarkable,but the activities of enzymes gradually increases after second and third treatments.Thus it is concluded that excessive silicate decreases the activities of SOD,POD,CAT,and PAL.Silicon concentration of 500～1000mg/L produces desirable effects.It raises the antioxidant ability of ginger leaves and increases the activities of defense enzymes.