Device and method for collecting water isotope sample in gas under normal pressure

The invention discloses a device and a method for collecting a water isotope sample in gas under normal pressure in order to solve the technical problem that the accuracy of a test result is affected due to the fact that a collected water isotope ratio is deviated from a real water isotope ratio in the gas in an existing collection method, and discloses the device and the method for collecting the water isotope sample in the gas under the normal pressure. The collecting device comprises a rigid gas collecting container, a water collecting unit and a vacuum pump; the rigid gas collecting container is used for collecting water-containing gas; the water collecting unit is used for adsorbing or freezing a water isotope sample in the water-containing gas; a monitoring unit is arranged on the rigid gas collecting container and is used for monitoring the internal environment of the rigid gas collecting container; a first valve for controlling water-containing gas to enter is arranged at the inlet end of the rigid ga