Abstract: The slurryability of lignite and its mixture with different percent of petroleum coke have been investigated. It was found that only 41% of lignite water slurry could be obtained at 1000mPa·s due to the strong hydrophility and macroporosity of lignite. With petroleum coke, the solid content of lignite water slurry has been progressively improved. The more petroleum coke, the higher concentration of mixture slurry. The solid content of slurry is allowed to be 60% when the mass ratio of petroleum coke to lignite is 3 to 2. All coke-lignite-water slurries exhibit pseudo-plastic behavior and good static stability. The hydrophility of lignite is strong, while petroleum coke is hydrophobic. The complementarity of lignite and petroleum coke plays the key role in getting high mass fraction of cokelignitewater slurries.