Abstract: Direct carbon solid oxide fuel cells (DC-SOFCs) are highly efficient power generation devices that can directly convert the chemical energy of solid carbon fuel into electrical energy. Modeling research has important guiding significance for the development of DC-SOFCs technology. However, current models of DC-SOFCs are steady-state simulation, which makes it difficult to analyze the evolution of DC-SOFCs performance over time. To address this problem, the consumption of solid carbon fuel is simulated by using the shrinking core model. The dynamic simulation of DC-SOFCs is carried out by combining the shrinking core model and the multiphysics coupling model to simulate the dynamic changes during the operation of cells. The impact of carbon fuel consumption on cells’ performance and stability is evaluated. The results show that the size of carbon particles gradually decreases over time, causing the change of CO concentration in the anode chamber, which in turn affects the performance of DC-SOFCs. Smaller carbon particles help improve the performance of cells, but their consumption rate is faster. The initial performance of cells with larger carbon particles is relatively low, but a relatively stable output performance of cells can be maintained.