As energy and environmental issues become more and more severe, fuel cell vehicles have received widespread attention due to their high efficiency (generally more than 50%) and environmental friendliness. However, durability, reliability, cost, and other issues still restrict the commercialization of fuel cells, which need to be solved through research. The fuel cell test platform is the basis for in-depth research on the reaction mechanism, dynamic model, system design, manufacturing, control, and optimization algorithms of fuel cell power generation systems. In the research process, water management is one of the crucial factors regarding the performance and durability of low temperature proton exchange membrane fuel cell. Nevertheless, the existing test platforms lack integrated fault diagnosis tools to identify flooding and drying of the fuel cell, which leads to the need for additional equipment when conducting water management research. Thus, in this work, a test platform for 2 kW low temperature proton exchange membrane fuel cell stack is designed with an impedance measurement system for fault diagnosis. In addition, because of the significance of water content inside the stack, a highly dynamic and high-precision humidification system is also needed. Therefore, the hardware and software of the experimental platform are designed respectively, especially the humidification system and the impedance measurement system. Besides that, the gas supply system, exhaust system, and thermal management system are also included. Finally, the test platform is tested in some experiments. The results prove that the software and hardware design is feasible and the function can meet the requirements for rapidity and accuracy.