Abstract: Infrared detectors play a crucial role in military, industrial, and medical fields. However, traditional materials have limitations: silicon-based detectors only cover the near-infrared range, HgCdTe is difficult to fabricate in large sizes and requires low temperatures, and GaAs is expensive and contains highly toxic arsenic. 2D materials, with their atomic-level thickness, tunable bandgap, and wide spectral response, have emerged as a key to breaking through these bottlenecks. This paper reviews the research progress: it first elaborates on five core working mechanisms such as photoconductive (PCE) and photovoltaic (PVE), as well as key performance indicators like responsivity and specific detectivity. Then, it analyzes three representative 2D material detectors: graphene achieving ultra-wide detection from 0.76 μm to terahertz, TMDs adapting to near and mid-infrared by layer number control, and black phosphorus improving stability through As doping. To address issues such as weak light absorption in 2D materials, optimization strategies are summarized: defect engineering, heterojunction regulation, and structural innovation, with some devices achieving responsivity up to 105 A/W and detectivity of 1014 Jones. Currently, challenges include difficult large-scale fabrication, material oxidation, and performance trade-offs. In the future, the development of new 2D materials and breakthroughs in batch fabrication techniques are needed, with customized devices for wearable and deep space exploration applications expected to achieve commercial substitution in key fields within 5-10 years.