To　study　the　influence　of　the　content　of　fly　ash　and　slag　and　the　proportions　of　slag-fly　ash　on　the　early-age　restraint　cracking　behaviors　of　concrete,　the　cracking　behaviors　of　concrete　was　analyzed　combining　the　test　of　the　evaporation　capacity　and　electrical　resisitivity　of　the　concrete　using　the　modified　flat-type　specimen.　The　results　show　that　the　optimal　content　of　fly　ash　and　slag　are　45%　and　40%　of　binder,　respectively.　Under　the　conditions　of　the　optimal　content,　the　early　age　cracking　behaviors　of　concrete　is　higher　than　other　content.　But　when　the　content　of　fly　ash　exceeds　60%　of　binder　and　that　of　slag　exceeds　50%　of　binder,　the　cracking　behaviors　of　concrete　rapidly　decrease.　The　cracking　behaviors　of　the　concrete　mix-tured　with　the　fly　ash　and　the　slag　is　higher　than　that　only　with　the　fly　ash　or　with　the　slag.　And　the　cracking　behaviors　of　concrete　with　1:1　of　the　proportions　of　slag-fly　ash　is　the　best.　The　relationship　between　the　cracking　time　and　the　lowest　value　of　electrical　resistivity　of　concrete　is　nonlinear.