The invention discloses an experiment system for simulating a nuclear containment benchmark accident condition and a realizing method of the experiment system, and solves the problem that the nuclear containment benchmark accident condition cannot be simulated comprehensively in the prior art. The experiment system comprises an experiment container, a first pressure sensor, a data acquisition system, an exhaust pipeline, an air supply system, a hydrogen supply system and at least four sampling pipelines, wherein the experiment container is used for loading a complete machine of a passive hydrogen recombiner; the first pressure sensor is arranged in the experiment container and used for detecting inner pressure of the experiment container; the exhaust pipeline, the air supply system, the hydrogen supply system and at least four sampling pipelines are connected with the experiment container; and the experiment container is connected with the data acquisition system through a multi-point thermoelectric couple. According to the experiment system for simulating the nuclear containment benchmark accident condition and the realizing method of the experiment system, the structural design is reasonable, the nuclear containment benchmark accident condition can be simulated really and comprehensively, the hydrogen elimination performance of the passive hydrogen recombiner is tested, a test result is very close to the actual condition, and accordingly, a terrific reference standard is further provided for study and design of the recombiner.