Organometal lead‐halide perovskites demonstrate excellent photovoltaic performance in the visible (Vis) region. However, their lack of response in the near‐infrared (NIR) region limits their applications in broadband photodetectors. Here, PbS quantum dots (QDs) were successfully embedded in MAPbCl0.5Br2.5 single crystal by solution‐processed epitaxial growth. Perovskites can effectively act as efficient charge transporters. The mobility of MAPbCl0.5Br2.5 with 1 wt% PbS quantum dots crystal is about 85 cm2/(V·S), which is similar to that of pure MAPbCl0.5Br2.5 single crystal. Meanwhile, the composite crystal exhibited a broadband response wavelength from the Vis (625 nm) to the NIR (850 nm) with fast response times (τon/τoff = 6/9 ms and τon/τoff = 19/43 ms in the Vis and NIR regions, respectively). The photodetector demonstrates a responsivity of 0.02 mA/W with a specific detectivity of 1.2 × 108 Jones under 5.1 mW/cm2 850‐nm illumination at 10‐V bias. These results suggest that we have obtained high‐quality composite crystals with improved photo response in the Vis to NIR region.