In　this　paper,　the　combination　of　fly　ash　and　silica　fume,　or　fly　ash　and　blast　furnace　slag　were　used　as　the　composite　mineral　admixtures　in　cement　paste.　The　autogenous　shrinkage　and　the　pore　structure　of　the　hardened　cement　paste　with　mineral　admixtures　were　tested,　and　the　relationship　of　the　autogenous　shrinkage　and　pore　structure　also　was　discussed.　The　results　indicate　that　fly　ash　can　reduce　the　autogenous　shrinkage,　and　silica　fume　can　increase　the　autogenous　shrinkage,　and　the　effect　of　blast　furnace　slag　is　between　the　two　above;　although　both　silica　fume　and　blast　furnace　slag　can　weaken　the　porosity　and　the　mean　diameter　of　cement　paste,　and　increase　the　volumetric　percentage　of　pores　whose　diameter　is　between　5　and　50　nm　and　pore　specific　surface,　silica　fume　is　better　than　blast　furnace　slag　in　changing　the　pore　structure.　The　relationship　between　the　autogenous　shrinkage　and　volumetric　percentage　of　pores　whose　diameter　is　between　5　and　50　nm　is　obviously　proportional.　Crown　Copyright　(C)　2010　Published　by　Elsevier　Ltd.　All　rights　reserved.