The invention relates to an intelligent expiration sampling method and device. The sampling method includes the steps that adjustment is carried out with the
differential algorithm, advanced intervention means are adopted, the complexity degree of a driving program is simplified, tiny adjustment is achieved, and flow changes tend to be gentle; flow is mutually matched with a tested person with theiterative
algorithm to seek the suitable rule, and the aim that flow is harmoniously and smoothly adjusted in a human-computer-
interaction mode is achieved; the sample device comprises a
breathing filtering module, a flow control module, a gas discharging device, a gas collecting device, a sensor, a
control unit, an interface and the like, and
during expiration, the flow is fed back to the
control unit through the sensor to control the flow control module to adjust the required flow;
airflow is completely discharged through the discharging device, then enters the gas collecting device to complete the sampling process, the intelligent flow
control algorithm is used in the flow control module according to
signal changes of the sensor, and human-computer-interaction operation and parameter setting are carried out on the interface.