Abstract: In this work, a stack composed of three flat-tube solid oxide fuel cells (SOFCs) was constructed, and a comparative analysis of the power generation characteristics of the stack under hydrogen and CH4/CO2 dry reforming conditions was conducted. This work investigates the influence of CH4/CO2 ratio and current density on the instantaneous and long-term reforming performance of the stack. Additionally, the performance changes of each individual cell are monitored. The results showed that the maximum power output of the 3-cell stack at 750 °C using hydrogen and dry reforming gas as fuels were 100.0 W and 81.1 W, respectively, with power consumption of the non-cell parts of the stack being 17.6 W and 9.8 W. During a constant current test at 15 A, the stack voltage degradation rate in a hydrogen environment after 100 h of operation was 0.130‰ h-1; under CO2/CH4 conditions, the stack voltage growth rate after 360 h of operation was 0.096 ‰ h-1. During long-term operation, the Cell-3, which is far from the fuel inlet, was the main factor contributing to the performance degradation of the stack. The results indicate the excellent stability of the flat-tube cells in the process of methane dry reforming.