The Er3+ doped laser gain medium around 2.7—3 μm with unique advantages has important applications in the fields of biomedicine, environmental detection and nonlinear optics, etc. However, the lower-level lifetime 4I13/2 is longer than that of upper-level lifetime 4I11/2, resulting in a high laser threshold, severe thermal effect and other problems. Some researchers devote to exploring laser gain media with low threshold and high beam quality by doping deactivate ions, thermal bonding, single crystal fiber (SCF), cascade laser, low photon energy and so on. Compared with other gain mediums in the same waveband, the Er3+ doped laser gain mediums have been rapidly developed and laser performance has also been improved obviously, which can be expected to further develop in its application field. In this paper, we summarize the research progress of the Er3+-doped laser crystal, such as YAG (Y3Al5O12), YSGG (Y3Sc2Ga3O12) and YAP (YAlO3), the Er3+-doped ceramics such as Y2O3, Lu2O3, the Er3+-doped zirconium fluoride glass such as ZABLAN (ZrF4-BaF2-LaF3-AlF3-NaF), and the relevant results and experimental protocol are highlighted. At the same time, we also look forward to the future development direction.