del was built to describe the ecological processes of an alkalinized–salinized meadow steppeecosystem, including the hydrological and alkalization-salinization processes in the soil, as well as the successionand growth dynamics of the grassland communities. A numerical integration model and a water and salt balancemodel were integrated into a physically-based model, describing the dynamics of soil moisture, salt concentration,exchangeable sodium percentage (ESP) and pH. Meteorological variables and soil characteristics were the mainenvironmental factors used to estimate the growth dynamics of three herbaceous communities that were dominatedby Aneurolepidium chinense, Chloris virgata, and Suaeda glauca, respectively. Model validation showed goodagreement between the simulated results and the observed data. Simulation studies were conducted to evaluate thepotential changes in hydrological and alkalization-salinization processes, succession and growth dynamics from1991 to 1998, under five grazing intensities, namely 0%, 25%, 50%, 75% and 90% above-ground biomass removal(AGBR). The simulations show that soil moisture decreased markedly under the 50%, 75% and 90% AGBR, butincreased slightly under the 25% AGBR. The de-alkalization and de-salinization processes would be predominantunder the 0% AGBR, and the processes became a little slower under the 25% AGBR. In contrast, the 50%, 75% and90% AGBR accelerated the degradation of soil properties. The grassland was dominated by A. chinense under the0%AGBR, and by A. chinense and C. virgata under the 25% AGBR. C. virgata could grow on slightly alkalinized-salinized soil and became a dominant species after three years of 50% AGBR. The soil degraded quickly and onlyS. glauca could grow on the severe alkalinized-salinized soil if the grassland received 75% or 90% AGBR. Thegrassland grew well under the 0% AGBR, and the biomass stayed at moderate level under 25% AGBR. The 50%,75% and 90% AGBR decreased the grassland growth greatly. After accumulating the grazed biomass for each year,the 25% AGBR would provide the highest production, and the grassland production would decrease sharply withthe increasing of grazing intensities. The simulation results indicate that 25% AGBR is significant for preservingthe soil from degradation, and maintaining high grassland production.