Abstract: Aiming at the status of low concentration (less than 49. 0%) of coal-water slurry from Inner Mongolia lignite which made it difficult for the gasifier to run n ormally. In this paper, primary process parameters of concentrated lignite preparation were obtained on the bases of investigations into the influences of temperature, s pecies and amounts of additives, and coal size-distribution on concentration of lignite. Besides, Aspen Plus was applied to simulate the gasification of lignite with variou s concentrations. The results showed that in the presence of compound additive of 0.5% mixed with 0.4% viscosity additive, a lignite with concentration of 54.1%, whi ch increased by 5.6% at 50。C compared with existing lignite with optimized coal size-distribution. Moreover, the data from gasification simulation demonstrated that the syngas production and cold gas efficiency of the concentrated lignite were 78. 07% and 70. 25% respectively, which were remarkably superior to that of existing lignite.