Abstract: Due to various advantages such as outstanding light absorption coefficient, long charge carrier diffusion distance, simple synthesis method, and low cost, halide perovskite materials, which are light absorption materials, are widely considered as promising candidates for next-generation electronic and optoelectronic devices such as solar cell, light-emitting diode, photodetector, laser device, X-ray imaging, and information storage devices. Particularly, since the introduction of halide perovskite-based solar cells in 2009, their solar conversion efficiency has increased from 3.8% to 23%, which is almost equal to that of commercial silicon cells, in less than ten years. However, the low phase stability, ion migration-induced hysteresis phenomena, and performance degradation significantly impede the further commercial application development of halide perovskite-based materials. Most recently, more attention has been paid to the zero-dimensional (0D) halide perovskite quantum dots (QDs) as compared to polycrystalline perovskite films because of their unique optical and electrical properties such as high crystalline quality and defect tolerance, flexible composition, quantum confinement effect, and geometric anisotropy. This paper summarized the limitations of the polycrystalline perovskite films and reviewed the intrinsic optical properties and detailed synthesis methods of halide perovskite QDs as well as their applications in optoelectronic devices. Specifically, the recent breakthrough on 0D-2D mixed-dimensional van der Waals phototransistors was systematically introduced. In addition, some perspectives of mixed-dimensional van der Waals phototransistors, which include interfacial charge carrier behavior modulation and subsequent construction of high performance photosensing device, were highlighted, and the corresponding scientific issues and challenges were discussed as well. Such comprehensive review is expected to be helpful for understanding and solving current issues faced in this research field; thus, it will effectively guide the evolution of the halide perovskite quantum dot materials and the development of perovskite-based next-generation optoelectronic devices in future.