An anesthesia machine exhaust emission control system detects a gas flow in a connection pipeline by an electronic flow detector and displays same by a display, and a controller controls, according to an operating state of the anesthesia machine, a switch so same turns on or turns off the connection pipeline. The method for controlling the connection exhaust emission control system comprises, directly displaying a gas flow value in the connection pipeline by the electronic flow detector, the controller and the display, so that the user can conveniently and accurately read the gas flow value in the connection pipeline. The connection pipeline is turned off when an anesthesia machine is in a standby status, thereby greatly saving exhaust gas recovery resources of a hospital.