HETS-ALK-S series test system provide a accuracy, reliable, and convenient test environment for alkaline (ALK) electrolyzer cells and electrolyzers. The HETS-ALK-S series consists of a gas-liquid separation unit, gas concentration detection unit, gas cleaning, cooling and drying unit, water-thermal management unit, pressure interlock control unit, measurement and control unit, and safety protection unit.Through online data monitoring and processing by HETS-ALK-S series test system, the performance, lifespan, reliability, and safety of the tested electrolyzer can be analyzed. HETS-ALK-S series test system is suitable for the research, calibration, and offline testing of ALK electrolyzers.