Summary: This work developed a copper-free 18F-labeling strategy using strain-promoted azide-alkyne cycloaddition (SPAAC) between dibenzocyclooctyne acid (DIBAC) and [18F]PEG-azide. The synthesis achieved high radiochemical yields (92%) and specific activity (254.69 GBq/µmol) within 90 minutes. Optimization studies demonstrated efficient labeling with substoichiometric DIBAC (0.2 mg). The method eliminates copper catalysts, ensuring biocompatibility, and offers rapid, chemoselective conjugation under mild conditions, making it suitable for PET tracer development.