High-density In-Al codoped ZnO (In, Al, ZnO) nanobunches are synthesized by using chemical vapor deposition method, which can be used to fabricate In, Al, ZnO nanobunches photodetectors. The ZnO nanobunches each have a hexagonal wurtzite structure. It is found that the average length of the nanobunches is ～5 m. The photoconduction mechanism and a series of photoelectric characteristics are studied including I-V characteristic measured in dark and UV illumination, responsivity and response time. The results indicate the presence of an internal gain mechanism. The response time is less than 0.5 s and decay time is about 23 s, so the fabricated device can indeed be used for light detection.