Objective To investigate the preparation of potato protein fiber (PPF) based on enzymatic method, and further analyze their structural and functional properties.Methods PPF is prepared from potato protein isolate (PPI) through enzymatic hydrolysis with trypsin (Tyr) and acid-heat treatment. The effects of protein mass concentration, heating time, Tyr activity, and heating temperature on the fluorescence intensity of PPF are studied. Structural properties of PPF are characterized by infrared spectroscopy, fluorescence spectroscopy, etc. With curcumin (Cur) as an encapsulated object, the encapsulation efficiency, loading capacity, thermal stability, and antioxidant activity of PPF-Cur complexes are investigated.Results During the fibrosis process of PPF, the β-sheet content increases from 28.12% to 32.29%, and the α-helix content increases from 22.53% to 25.87%. When the protein mass concentration ranges from 0.2 to 0.8 mg/mL, the Trp fluorescence peak of PPF exhibits a redshift, and its fluorescence intensity is higher than that of PPI. When the Cur concentration increases from 20 to 100 μg/mL, the encapsulation efficiency of PPF-Cur increases from (64.66±0.25)% to (96.16±0.20)%, representing a 48.72% increase, while the loading capacity increases from (3.25±0.01) to (19.62±0.02) μg/mg, a 5.04-fold increase. After heating for 120 min, the retention rates of free Cur and PPF-Cur are (74.40±0.32)% and (87.83±0.61)%, respectively. At Cur concentrations of 20~40 μg/mL, the scavenging rates of PPF-Cur against DPPH free radicals and ABTS? free radicals reach 66.46% and 47.87%, respectively.Conclusion Food protein fibers prepared by enzymatic method combined with acid heat treatment can improve the structural and functional properties of proteins.