The invention discloses a cluster-type small-volume target damage image collecting system and a collecting method thereof. According to the cluster-type small-volume target damage image collecting system, a plurality of collecting devices provided with brake parachute devices are arranged in a groove of a host ammunition, and a cover plate is installed on a shell body of the host ammunition through a connecting part; the collecting devices and the brake parachute devices are correspondingly connected to a mooring rod part through triggering parts; when the host ammunition is launched, a control system sends a separation signal to the connecting part, the connecting part is broken, the triggering part is pulled by the mooring rod part, thus the collecting devices are triggered to start, andmeanwhile parachute packs of the brake parachute devices are opened; the collecting devices collect image data below and send the image data outward; image collection is synergistically conducted through a plurality of sensors, the collecting field of the image collection is effectively enlarged, and thus the effectiveness of detecting the droppoint area of the ammunition is improved; and the three-mode image information collection combines infrared, ultraviolet and visible light, a plurality of the collecting devices collect by division of work, and the image information of a multispectral band in the droppoint area of the ammunition is obtained.