The invention discloses a single-point sampling detection system with micro pressure, which belongs to the technical filed of sampling device. The detection system is characterized in that: the inletend of a conveying tube (10) is communicated with the outlet end of the conveying tube, and the outlet end of the conveying tube (10) is connected in series with a color-comparison tube (7) and is communicated with an adsorption tank (9). The inlet end of a return tube (26) is communicated with the outlet end of the conveying tube (10), and the outlet end of the return tube (26) is communicated with an inlet tube. A sampling check valve (22) is provided between the conveying tube (10) and the inlet tube. A return check valve (23) is provided on the return tube (26). A sampling valve (5) is provided between the conveying tube (10) and the color-comparison tube (7). The inlet tube is provided with an inlet valve (1). A pressure boosting device is provided between the conveying tube (10) andthe inlet tube. According to the single-point sampling detection system with the micro pressure, samples taken by the single-point sampling detection system with the micro pressure are representativeand easy to operate during sampling; and medium leakage during sampling and pollution to the environment are avoided, thereby having a wide application range.