Ice　slurry　is　a　really　interesting　technology　thanks　to　the　high　energy　storage　density　given　by　the　latent　heat　of　phase　change　and　the　fast　cooling　rate　because　of　the　large　heat　transfer　surface　area　created　by　its　numerous　particles.　The　size　distribution　of　ice　particles　is　a　very　important　aspect　for　ice　slurry　system　because　it　influences　the　fluidity　and　heat　transfer　performance　of　ice　slurry.　In　this　study,　the　effects　of　ethylene　glycol,　nano-SiO2　and　the　ice　packing　fraction　on　the　ice　particle　size　were　examined　respectively　by　a　microscopic　observation　system.　It　was　found　that　ethylene　glycol　could　reduce　the　ice　particle　size　effectively　due　to　the　hydroxyl-containing　structure.　The　average　ice　crystal　diameter　was　decreased　from　85.7ìm　to28.3　ìm　when　the　volume　concentration　of　ethylene　glycol　was　varied　from　1%　to　15%.The　influence　of　the　ice　packing　fraction　on　ice　crystal　size　distribution　was　not　very　significant.　In　addition,　adding　a　small　amount　of　nano-SiO2　into　ethylene　glycol　solution　could　produce　smaller　and　rounder　ice　crystals　than　without　nano-SiO2.　Therefore,　it　can　be　expected　that　Nano-SiO2,　used　as　the　nucleating　agent,　is　a　promising　additive　in　ice　slurry　system.