The utility model discloses a fiber cutting device for synchronous asphalt and macadam sealing vehicle or equipment. The fiber cutting device comprises a fiber material, wherein the fiber material is arranged on the sealing vehicle or equipment; a steel pipe channel for introducing the fiber material is arranged above the fiber material; one end of the steel pipe channel is connected with a hose channel which extends downwards and is used for introducing the fiber material into a fiber cutting assembly arranged below the sealing vehicle or equipment; the fiber cutting assembly comprises at least one rotary cutting tool which is used for cutting the fiber material into a certain length; the fiber cutting assembly comprises a driving wheel which is driven by a hydraulic motor; the driving wheel is adjacently close to the rotary cutting tool which is driven through mutual friction force; a high-pressure air blowing nozzle with a construction pavement capable of uniformly blowing away the cut fibers is arranged below the rotary cutting tool; and the rotary cutting tool is connected with a cutting knife switch cylinder which is used for achieving fiber spreading width adjustment.