Abstract: Radio-isotopes of noble gas, which are produced during nuclear explosion, can escape into atmosphere easily. These isotopes can be measured as good indicators for nuclear explosion. Noble gas monitoring, including sampling, measurement and analysis, became more and more essential. Gas chromatography is an important technology on noble gas separation during gas sampling. In this paper, while 5 molecular sieve was utilized as column stationary state and high-purity nitrogen as column fluid state, resolutions of argon, krypton, xenon and radon were widely investigated under different chromatograph conditions. As a result, the resolution of krypton and argon is less than the resolution of xenon and krypton; when column flow rate is 35.6 mL/min and oven temperature is 353 K, all of the resolutions of radon and xenon, xenon and krypton, krypton and argon are more than 2.25.