Abstract A 3-cell stack of anode supported planar solid oxide fuel cell was built to evaluate the application of an external-manifold design in this research. This short stack was operated with hydrogen as fuel and air as oxidant at 750 °C. The stack had an OCV of 3.36 V, produced about 100 W in total power with a power density of 0.56 W/cm2. The stack also underwent 51 h degradation test at the current density of 0.55 A/cm2. The test results have demonstrated that this external-manifold stack had an excellent and steady performance during the test. Computer simulation was employed to help optimizing the parameters of the design and explaining the different performances between the cells. The simulation results suggested that the external-manifold design could generate a uniform gas distribution for a short stack, and the different performances of the individual cells were mainly caused by the uneven temperatures distribution between the cells.