Abstract: In order to further improve stability of lignite coal water slurry,Turbiscan Lab stability analyzer was applied top study naphthalene series dispersant and ligni n series dispersant affected to stability of lignite coal water mixture. The results showed that stability index TSI values of lignite coal water slurry were all small and stability was excellent. During the settling process,coalescence between coal particles could reduce stability of coal water slurry. The lignite coal water slurry was prepared after lig nin series dispersant added,the thickness of slicing would be reduced,the settling speed would be reduced, the agglomerate phenomenon of particles would be weaken and stability would be better than only application of naphthalene series dispersant. The Turbiscan Lab stability analyzer could realize real time analysis on stability of coal wat er slurry and could provide technical references to selection and utilization of dispersant. Keyword: lignite; coal water slurry; dispersant; stability analyzer;