Abstract: The co-slurryability of water hyacinth and Shenfu coal was investigated with 2 dispersants, methyl-naphthalene sulfonate sodium formaldehyde condensate (MF) and modified sodium lignosulphonate (B1). The results show that when mixing 19.16g water hyacinth into 100 g coal, the apparent viscosity of coal-hyacinth slurry (60%) was 1154mPa·s using MF as dispersant; and it decreased to 999mPa·s while water hyacinth is modified by Fe₂(SO₄)₃.Using B1 as dispersant the apparent viscosity of coalhyacinth slurry (60%) decreased slightly. Fe₂(SO₄)₃ reduced the number of hydrogen bonding oxygen-containing functional groups, and increased the content of free water in hyacinth. The stability of coal-water slurry is improved by adding water hyacinth, and the sedimentation time increases from 2h to 60h. Fe₂(SO₄)₃ can further improve the stability of coal-water slurry with sedimentation time up to 88h. The hydrophilic oxygen-containing functional groups and cellulose in water hyacinth play the key role in improving the stability of coal water slurry.