In this paper, the performance and durability of a self-designed proton exchange membrane fuel cell (PEMFC) stack with 5 single cells are investigated with in-situ segmented cell technology. Effect of dummy load application during shut-down process on performance degradation is analyzed through measuring polarization curves and electrochemical impedance spectroscopy (EIS) after different start-up and shut-down (SU/SD) cycles. Scanning electron microscope (SEM) images of membrane electrode assembly (MEA) are taken after the SU/SD cycles. According to the analysis results, it is confirmed that dummy load can take benefit to the durability of PEMFC during the SU/SD process and also the uniformity of current density in different regions for each single cell. However, dummy load may not affect the uniformity of single cells for the stack. This paper contributes to the strategies for promoting performance and durability of PEMFC stack.