As a biodegradable material, poly(glycolic acid) (PGA) has emerged as a green alternative to conventional oilfield materials, addressing pollution and formation blockage challenges through its high strength, high-temperature resistance, and controllable degradability. However, PGA still faces limitations such as insufficient stability in high-temperature/high-salinity environments, imprecise regulation of degradation rates, and elevated production costs. The article systematically reviews PGA synthesis methods, including direct polycondensation, ring-opening polymerization, and coal chemical synthesis routes. It comprehensively analyzes PGA's physical properties, mechanical performance, thermal stability, and degradation behavior, with particular emphasis on its high strength, pressure resistance, and controllable degradation advantages under oilfield high-temperature/high-pressure conditions. The review highlights recent advances in PGA modification strategies, covering molecular structure optimization in copolymerization and interface compatibility enhancement in blending modification. Finally, it discusses critical technical challenges in thermal stability control and precise degradation rate regulation, while envisioning PGA's application potential in intelligent temporary plugging and reservoir protection for sustainable oilfield engineering.