The invention discloses a miniature semi-active folding flapping wing, which consists of a front beam, an inclined beam, wing ribs and covers. The front beam and the inclined beam are respectively divided into two sections from an middle part; the inner section and the outer section of the front beam are respectively fixed to a folding base and a folding head; a rocker arm of the folding head is connected with a soft steel wire rope; the soft steel wire rope penetrates through the inner section of the front beam and is fixedly connected with a frame of a flapping wing driving mechanism; and a root part of the inner section of the front beam is connected with an output rocker arm of the flapping wing driving mechanism in an inserting manner. In a process that the flapping wing downwardly flaps, the flapping wing keeps flat and straight, and in an upwardly flapping process, the outer section of the flapping wing is downwardly bent to a certain angle due to the action of aerodynamic forces, and further, gradually becomes flat and straight along with the straining of the steel wire rope. According to the miniature semi-active folding flapping wing, the asymmetric upward / downward flapping of the flapping wing is realized through a simple and reliable manner, a resultant force of the aerodynamic lifting forces in a flapping cycle is increased, the aerodynamic efficiency of the flapping wing is increased, and thus, the miniature semi-active folding flapping wing is applicable to a miniature flapping wing flying vehicle.