Abstract: Radionuclide verification is one of four international monitoring systems that were stipulated by the comprehensive nuclear test ban treaty. The radioactive noble gas xenon is a gaseous fission product of nuclear fuels. The radionuclides of Xe are characteristic nuclides of nuclear explosion. A nuclear event that violates the treaty may be found by monitoring the variation of radioxenon (mainly ¹³³Xe^m, ¹³³Xe, ¹³⁵Xe and ¹³¹Xe^m) in global atmosphere through a global network of eighty stations of the international monitoring system (IMS). Therefore, it is necessary to research the sampling technology for xenon isotopes. The possibilities for sampling technology (including condensation and concentration of xenon isotopes) is explored from preseparating and precondensing microxenon sample with FNQ-01 gas condenser experimental platform. The collecting efficiencies of microxenon influenced by the different condensing conditions were studied on this experimental platform. The best condensing conditions optimized with the orthogonal design method are showed respectively as follows: xenon concentration in sample 1.046×10^-3, condensing temperature -198 ℃, gas flow rate 0.3 L/min, gas inlet pressure 55 kPa and evaporating temperature -50 ℃. The average collecting efficiency under these optimized conditions is 73％. Furthermore, the influences of different admitting methods to xenon collecting efficiency and condensation were discussed.