Abstract: This paper focus on the Xinyang coal gangue fly ash high concentration backfill slurry characteristics. The mechanic model was established to research the coal gangue suspension within the high concentration slurry and theoretical analysis was carried out to study the potential influence factors to the coal gangue suspension.The results show the most significant method to enhance the coal gangue suspension is to improve plastic viscosity and yield stress of the high concentration slurry.The suspending agent that employed in the slurry configuration is to enhance the slurry plastic viscosity , resulting in improving the coal gangue suspension characteristic and decreasing the coal gangue fall downward speed.'The results reveal that the excessive amount of additive less the fluidity of the slurry , increase the slurry pipe transportation resistance.Coal gangue remains suspension characteristic in Xinyang high concentration slurry when the slurry viscosity range from 3.24 to 3.40 Pa · s while the slurry yield stress is between 107.9 to 111.9 Pa.At this level of rheology characteristics , the slurry is adequate to transport.