The invention discloses a flow control sealing mechanism and a yarn hairiness detection method based on the same. A circular spray pipe and a circular suction pipe right below the same are arranged ina shade of the flow control sealing mechanism; the circular spray pipe is provided with a plurality of nozzles which open downward; the circular suction pipe is provided with a plurality of nozzles which open upward. The flow control sealing mechanism and the yarn hairiness detection method based on the same have the advantages that the flow control sealing mechanism ensures cleanliness of an instrument test zone during testing, lodging of hairs is never caused due to air resistance, tips of hairs and yarn shanks are freely stretched, and therefore, image quality is improved and accuracy of test results is guaranteed; a central control system ensures action phase difference precision for a power supply source and an image acquirer; detection state is truly provided for moving yarns duringoperating, and reliable dynamic instrument state detection can be performed after static calibration; a light source has a high duty ratio, so that the heat problem is avoided.