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The Ag/SnO2 composites were prepared by reactive synthesis and the microstructure uniformity and performance variation of Ag/SnO2 composites in the severe plastic deformation were investigated. The SEM analysis shows that with increasing of true strain, the fiber like microstructure vanishes gradually, and the distribution of SnO2 particles changes from cluster like to uniform. The test results of electrical and mechanical performances as well as grain sizes indicate that the performances of the Ag/SnO2 composites by severe plastic deformation are improved greatly, their mass loss of the contacts via larger true strain extrusion decreases obviously.