The　effects　of　erosion　mode,　erosion　age,　and　concentration　of　sulfate　solution　on　mechanical　properties　of　concrete　were　investigated.　The　dimensionless　relationship　model　of　the　stress-strain　of　concrete　on　the　basis　of　randomness　was　proposed.　The　variation　of　the　elasticity　modulus　and　Poisson＇s　ratio　of　the　concrete　surface　attacked　by　sulfate　was　studied,　and　a　novel　method　of　using　a　superficial　parameter　to　characterize　the　performance　change　of　the　concrete　surface　was　recommended.　The　results　showed　that　the　dimensionless　relationship　model　of　stress-strain　of　concrete　could　be　used　to　represent　the　variations　of　mechanical　properties　of　concrete.　The　differences　of　load-displacement　of　concrete　before　and　after　sulfate　attack　were　reflected　as　the　change　of　curve＇s　slope　and　ultimate　bearing　capacity,　and　the　slope　of　a　straight　section　of　the　lateral　and　longitudinal　strain　curves　of　concrete　surface　also　varied.　The　increment　rates　of　ultimate　bearing　capacity　of　concrete　attacked　by　1%　and　saturated　sulfate　solution　were　about　30%　and　10%,　respectively.　However,　the　decreasing　ratio　of　the　ultimate　bearing　capacity　of　concrete　attacked　by　saturated　sulfate　solution　was　approximately　25%.　The　damage　factor　of　the　elasticity　modulus　of　the　concrete　surface　of　C20　and　C40　was　0.185　and　-0.19,　respectively.　The　obtained　results　could　provide　a　support　for　investigating　the　variations　of　stress-strain　relationship　and　mechanical　performance　of　concrete　under　a　sulfate　environment.