It’s necessary to establish a high-precision analytical system of Gas Chromatography (GC) and be validated online for achieving the demand of trace components in fuel cycle system of fusion reactors. The paper explained that it was an effective measurement of trace components analysis in process gas by chromatography self-developed, with better repeatability (RSD < 3.0%), lower detection limit (DL < 10 ppb), better resolution (Re > 1.0) and higher relationship between area and concentration (R2 > 0.99) for each component. It’s illustrated that the self-development GC analysis system was satisfied to the test requirements, while the measurement was accurate and effective. Besides, it was useful to analysis of the online verification testing of molecular sieve penetration bed and impurity removal bed, which could calculate the adsorption capacity and the efficiency of impurity removal, respectively. According to the results of testing, we could make sure that they applied to the purpose of tritium blanket module (TBM), further, the fuel cycle system of fusion reactors could acquire basis data with these results.