The invention discloses an online stroboscopic detection and automatic splicing device for composite equipment, and mainly relates to the technical field of composite machining equipment. The online stroboscopic detection and automatic splicing device comprises a first guide roller, a second guide roller, a third roller and a winding roller. A stroboscope is arranged at the front end of the first guide roller, a paper storage unit is arranged between the second guide roller and the third guide roller, and the first guide roller and the third guide roller are both connected with the winding roller through a splicing unit. A stroboscopic detection lamp is arranged on the surface of the stroboscope which is connected with an external controller. The paper storage unit comprises nine sets of paper guide rollers and transmission rollers. The splicing unit comprises a press-fit roller, an automatic phase control system and a cutter driving device. According to the online stroboscopic detection and automatic splicing device, online automatic detection is achieved in the whole process, shutdown processing is not needed, and the purposes of saving materials, reducing manpower and improving quality and efficiency are achieved.