Owing to its high carrier mobility, electrical conductivity, and thermal/chemical stability, graphene is an ideal candidate material for photodetection. However, the weak light absorption of graphene significantly limits its practical applications in photodetectors. Quantum dots, with strong light-absorption capacity and well-adjustable band gap, are widely hybridized with graphene to realize wide-range and intense light absorption for effective photodetection. A detailed literature review on graphene/quantum dot heterostructure photodetectors is in urgent need to clearly point out the fundamentals, material synthesis methods, and performance engineering strategies. Here, first, the significance of graphene/quantum dot heterostructure photodetectors, from the mechanism to performance indicators, is systematically discussed. Second, different synthesis methodologies for the graphene/quantum dot heterostructure are overviewed. Additionally, the engineering strategies, including surface treatment, chemical doping, and size modification, to tune the photoelectric performance are critically commented. Finally, challenges and outlook for the development of graphene/quantum dot heterostructure photodetectors are pointed out.