The　rutile　SnxRu1-xO2　(0≤x≤1)　structures　were　calculated　by　the　first-principles　on　density　functional　theory　(DFT)　and　optimized　by　local　density　approximation　(LDA).　The　changes　in　the　lattice　parameters　with　the　increase　of　tin　were　shown.　A　function　between　the　cell　volume(V)　and　the　solid　solubility(x)　could　be　fitted,　and　then　the　precise　researches　on　the　structures　of　SnxRu1-xO2　solid　solutions　could　be　realized,　which　are　in　good　agreement　with　the　practical　results.