Abstract: Non-radioactive gaseous tracer technology is a kind of common leakage testing method. SF₆ is one of the most popular tracer gas. On-line analyzing testing system for SF₆ tracer is important to the leakage tests in some special scenarios, such as the dynamic leakage testing of large containers for poisonous or radioactive gas, wherever they are located on or under the earth. A remote controlling system for SF₆ on-line sampling and analyzing was established in this paper, on the base of modular design along the tracer’s leakage testing processions, such as instrumental adjusting, washing, sampling, analyzing, etc. The running system doesn’t decrease the analyzing ability of the gas chromatograph for SF₆. The sampling volume is less than 35 mL through precious pressure control, the baseline noise is almost the same as the gas chromatograph itself, the analyzing precise for a single sample with different testing channels in a long time is better than 1%, and there is no cross contamination among samples. Errors of the temperature and pressure of the leaking gas are in the range of the in-situ measure instruments.