This paper discussed the biomass growth and consumption processes in grazed pasture ecosystems from a theoretical point of view, simulated the dynamics of these two processes with mathematical models, and analyzed the mechanism of ecological balance in pasture ecosystems from the perspective of these two processes. With the proposed biomass growth and consumption models, the dynamics of cumulative biomass consumption during one production cycle was simulated, and the optimal grazing strategies of pastures were proposed. The results could be valuable for pasture grazing management in practice.