W-Re alloys are one of the most important refractory materials with excellent high-temperature performance that were developed to improve the brittleness of tungsten. In the present work, we firstly summarized the research progress on the preparation and strengthening methods of a W-Re alloy. Then, the strengthening mechanisms of the W-Re alloy were discussed, including the influence of Re, solid solution strengthening, second-phase reinforcement and fine-grain strengthening. The results showed that the softening effect of Re was mainly related to the transformation of the preferred slip plane and the introduction of additional d-valence electrons. Some transition elements and refractory metal elements effectively strengthened the W-Re alloy. Carbides can significantly enhance the high-temperature mechanical properties of W-Re alloys, and the reasons are twofold: one is the interaction between carbides and dislocations, and the other is the synergistic strengthening effect between carbides and Re. The objective of this work was to enhance the comprehension on W-Re alloys and provide future research directions for W-Re alloys.