In this paper, we present a study of the magnetic coupling and magnetoresistance (MR) properties in Fe/Si1-xAgxmultilayers with a granular Si1-xAgx spacer layer. We have found that, with increasing silver content (x) in a siliconmatrix, the magnetic state of multilayers changes from a nonmagnetic coupling state to weak antiferromagnetic aroundthe percolation point of the ～2.4 nm thick spacer Si1-xAgx. The MR measurements also reveal an abrupt increaseof MR near the same percolation point. These changes are ascribed to the formation of the percolation path in thegranular spacer.