The invention relates to an intelligent stroke-selection water saving device which comprises an infrared sensor, wherein the signal output end of the infrared sensor is connected with the signal input end of a singlechip microcomputer together, the output end of the singlechip microcomputer is connected with the input end of a first electromagnetic valve, two electromagnetic valves are connected to the lower side of the first electromagnetic valve in parallel and used for controlling water quantity, and the electromagnetic valves are respectively connected with a water inlet pipe and a water outlet pipe. According to the invention, the third-generation infrared pulse sensor is used for receiving infrared rays emitted from the human body, appropriate water quantity and time duration can be intelligently selected by using the singlechip microcomputer according to the pulse triggering frequency, and a waterflow output mode is controlled for realizing intermittent water flushing. Under the unmanned condition, the electromagnetic valves are closed and water is not drained; and when a person is present, water is intermittently drained for realizing intermittent flushing.