Abstract: In order to help researchers of coal mine well understand basic properties of tube bundle system (TBS) which includes positive pressure gas transmission and negative pressure gas transmission in gas sampling, two experiments were designed in this paper. One experiment was designed to test the relationship of the length of TBS and the time of gas sampling for both positive pressure and negative pressure, and the other experiment was designed to test the relationship of the length of TBS and the final flow of gas sampling. Two empirical functions were constructed to fit the experimental data. Based on results of empirical functions, the tests indicate that positive pressure gas transmission has shorter sampling time and larger sampling flow than that of negative pressure gas transmission.