Abstract: In order to study the localization of calmodulin in the plant cell and it's biological function,gene constucts containing the fusiongene(cam·gus)under the control of the 35S CaMV promoter or the pollen specific promoter LAT 52-7 from tomato,were in troduced into Nicotianatobacum cv.SRI by leaf disctrans for mation respectively.GUS reaction show that in the tran sgenicline pMD CaM·GUS,the fusion protein CaM·GUS was widely observed in roots,stems and leaves.And it had a higher levels throughout the cytosal of root meristem region,quiescence center cell,root hair cells,epidermal cells,and vascular cells.CaM was also detected in polar distributionsty leunder the membrane of the jointsite between-guard cells.Inp BILAT·CaM·GUStran sgenic line,CaM only localized in the cytop last of pollen grains,and a higher expression of CaM was detected at germination zones.Our results show that Ca Mex hibitsa symmetric distribution the plant cells,which has a very tight relation ship with cell biological function.