The　effects　of　quality　and　content　of　fly　ash　on　the　early-age　cracking　behavior　of　high-flowing　concrete　(HFC)　were　investigated.　The　early-age　cracking　behavior　of　the　HFC　was　analyzed　by　combining　the　tests　of　evaporation　capacity　and　electrical　resistivity　of　the　HFC.　In　these　tests,　a　modified　flat-type　specimen　was　adopted.　The　results　show　that　the　HFC　will　have　a　lower　evaporation　capacity　when　it　is　mixed　with　fine　fly　ash,　while　it　will　have　a　higher　evaporation　capacity　when　grade　III　fly　ash　is　used　as　mineral　admixture.　And　the　electrical　resistivity　rate　of　HFC　reduces　with　the　increase　of　the　content　of　fly　ash.　A　nonlinear　relationship　exists　between　the　cracking　time　of　HFC　and　the　minimum　electrical　resistivity.　The　early-age　cracking　behavior　of　HFC　with　fly　ash　can　be　enhanced　by　appropriately　increasing　the　fine　particle　content　and　MgO,　K2O,　and　SO3　contents　of　fly　ash.　The　optimal　content　of　fly　ash,　which　makes　a　satisfied　early-age　cracking　behavior　of　HFC,　is　obtained.　And　when　the　content　of　fly　ash　exceeds　a　critical　value,　the　early-age　cracking　behavior　of　HFC　will　rapidly　decrease.