Abstract: In order to study the influence of coal gangue large particle size coarse aggregate ratio to filling body property，filling paste was made from broken coal gangue，flyash and cement，the quality ratio of the large particle size corase aggregate were 0，5%，10%，15% and 20%，respectively.And slump，initial setting time，final setting time，uniaxial compressive strength after curing 1d，3d，7d，28d were test，respectively.The experimental results showed that the ratio of large particle size had large influence to filling paste flowing property，when quality density unchanged，the flowing property would be became worse with the large particle size coarse aggregate ratio increase.The slump of filling paste decreased from 226mm to 176mm under experimental ratio，but initial and final setting time unchanged basic，the early strength of filling paste test specimen changed almost small，but long-term strength increased as quasi-linear trend with the large particle size ratio increased，and reached 4.018MPa at the end.The filling paste property was the best as the ratio of 15～25mm coarse aggregate was 15%.