The 3-5 μm mid-infrared laser can be used in infrared countermeasures, biomedicine, atmospheric remote sensing and environmental monitoring. All solid-state lasers using LD directly pumped laser materials become a main output method for mid infrared lasers due to their advantages like simple system, high conversion efficiency, and good beam quality. Polycrystalline transparent ceramics are commonly used as laser materials due to their preparation easiness, superior thermal and mechanical properties as well as the ability to achieve high doping concentrations. However, the development of high-power lasers requires overcoming the inevitable thermal effects during laser operation, i.e., thermal birefringence, thermal lensing, and depolarization, which arise from the temperature gradient inside the laser material. It is crucial to use laser materials with a high thermal conductivity to alleviate thermal effects and ensure the quality and stability of laser output. Moreover, laser host materials must also have a lower phonon energy to suppress non-radiative transition processes that compete with the luminescence processes. It is thus difficult for materials to simultaneously possess all of these properties. In recent years, a large number of reports have claimed that Y2O3-MgO nanocomposite ceramics have ideal properties required for laser host materials, including high infrared transmittance, low phonon energy, high thermal conductivity, and good mechanical properties. The microstructure and properties of Y2O3-MgO nanocomposite ceramics doped with rare-earth activation ions are investigated, indicating that nanocomposite ceramics can be used as potential host materials for mid infrared lasers.This review summarized the existing research results of Y2O3-MgO nanocomposite ceramics as a laser host material and also represented recent technologies and methods for preparing Y2O3-MgO nanocomposite ceramics.The existing studies by theoretical models and experiments indicate that Y2O3-MgO nanocomposite ceramics have a high thermal conductivity, compared with Y2O3 ceramics, and a low maximum phonon energy (591cm-1). This is due to a synergistic effect of composite properties, combined with a high thermal conductivity of the second phase MgO and a low phonon energy of Y2O3. However, the optical transmittance of Y2O3-MgO nanocomposite ceramics is mainly affected by grain size, porosity, and phase domain distribution, which makes it imperative to improve their microstructure. Therefore, some technologies and methods for preparing ceramics are emerged, i.e., colloidal forming, two-step sintering, high-pressure sintering, and reducing a difference in refractive index between the two phases. Moreover, the research results of rare-earth ion doped nanocomposite ceramics, such as Er：Y2O3-MgO and Ho：Y2O3-MgO, also confirm that the introduction of high thermal conductivity MgO can effectively improve the thermal conductivity of ceramics without affecting the photoluminescence properties of the luminescent components, indicating that Y2O3-MgO nanocomposite ceramics can be used as promising laser host materials.Summary and prospects Y2O3-MgO nanocomposite ceramics are promising laser host materials. However, there is still a gap between the optical quality requirements of Y2O3-MgO nanocomposite ceramics and infrared laser materials, even though researchers have made significant efforts to improve the microstructure of Y2O3-MgO nanocomposite ceramics. This leads to the preliminary characterization and analysis of the photoluminescence characteristics of rare-earth ion doped Y2O3-MgO nanocomposite ceramics, and has not yet achieved infrared laser output. There are still some aspects that need further research and exploration before its practical application: 1) Developing preparation methods and optimizing processing parameters are the main direction of future research to obtain the dense samples, while effectively suppressing their grain growth. If the grain size is small enough, it is expected to expand the transmittance range of Y2O3-MgO nanocomposite ceramics to the visible light band and apply it to the field of mid infrared lasers, 2) Different activation ions and pump light sources are needed to be selected for laser output at different wavelengths, and even sensitizers need to be added to match the existing pump light. As a result, it is necessary to investigate the influence of rare-earth dopants on the microstructure, thermal properties, optical properties, and laser output performance of nanocomposite ceramic systems, and 3) In order to expand the selection range of laser host materials, a further diversified research on nanocomposite ceramics needs to be carried out.