This study explores the potential of recycling and utilizing discarded wind turbine blades. It proposes a new method that upcycles the glass fiber powder (GFP) in these blades into geopolymer gel, offering a new solution for the recycling and treatment of retired wind blades. Analyses of the X-ray diffraction (XRD) pattern of the GFP raw material and its dissolution in concentrated alkali indicate a large content of vitreous and active silica-aluminum, suggesting its suitability for producing geopolymers through alkali activation. The effects of the alkali activator modulus (Ms), alkali-binder ratio (N/B), and water-binder ratio (w/b), raw material particle size, and initial curing temperature on the compressive strength of the specimens were comprehensively and systematically investigated. The reaction behavior, chemical structure, and microstructure of GFP-synthesized geopolymers were characterized by selective dissolution, microcalorimetry, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS). The results showed that gels were formed by the geopolymerization reaction between the GFP and alkali activator. The compressive strength of the specimens increased first and then decreased with increasing alkali activator Ms and N/B. However, increasing w/b led to a decrease in strength. Appropriately small particle sizes of the raw material and moderately increasing the initial curing temperature are beneficial to strengthen the compressive strength. The optimal 28 days compressive strength of 43.43 MPa was achieved with an activator Ms of 1.4, N/B of 10 %, w/b of 0.33, GFP with a D90 of 170 mesh, and an initial 24 h curing temperature of 60 °C. The results of this study can promote the utilization of waste wind blades in the production of sustainable building materials.