The research and application of gob-side entry retaining (GER) technology in Chinese coal mines has been over 60 years. Two major technical types including GER with filling and GER with roof cutting were developed. However, due to the complex mining and geological conditions of the mined-out coal seam in different mining areas, as well as the strong mining pressure behaviours in the retained roadway, the promotion and application of GER technology presented ups and downs. Firstly, the achievements and key technological advances in the main GER types in China, the principle of surrounding rock stability, road-in support technology, roadside support technology, adaptability evaluation and surrounding rock stability monitoring are summarized, and the application applicability of different technologies at this stage is analyzed. Then, the difficulties and challenges faced by current GER technology are summarized: there is still no systematic theory for GER with strong mining pressure; there are still shortcomings in the theoretical understanding of the interaction mechanism between the surrounding rock and the support body for GER with filling; the mechanical and deformation characteristics of the filling materials for the roadside support body are not yet suitable for GER in deep working faces or with strong mining pressure; the mechanism and control technology of floor heave for GER are not yet perfect; the research on stability control of filling body for GER under strong dynamic load or rock burst is still in a blank. Finally, concerned with such difficulties and challenges, several reserve technologies have been proposed: the coordinated control of controlled roof cutting and filling for GER in fully mechanized caving/ full-seam mining in the thick coal seam, and the GER technology with additive modified high-water materials in working faces with strong mining pressure; finally, a set of intelligent inversion workflow for rock mechanical parameters used in GER numerical simulations for GER is established, and an intelligent optimization design method for GER support parameters is proposed