Abstract: The startup and stop threshold of hydrogen recombination and the hydrogen removing rate are key performance indexes for the passive autocatalytic hydrogen recombiner (PAR). A straightforward and convenient experimental method for validating the performance of PAR is proposed. Put PAR in an airtight vessel, and hydrogen is feed to the vessel. If the PAR start hydrogen recombination and whole inlet hydrogen concentration variation curve versus time is under given line A, the startup threshold is confirmed to be not greater than A. If the final horizontal segment of the inlet hydrogen concentration variation curve versus time is under given line B, the stop threshold is confirmed to be not greater than B. If PAR realized steady operation status, the average flow rate of hydrogen fed into the vessel is the hydrogen removing rate. Test rig is designed and setup, and the experiment for validating the performance of PARQX-15 PAR is carried out. Successfully, the startup threshold is confirmed to be not greater than 2(v)%, and stop threshold is confirmed to be not greater than 0.5(v)%, and the hydrogen removing rate is greater than 536 g/h. Conclusion can be made that this method is practical and effective.