Abstract: This study aimed to synthesize APPCS-SeNPs and evaluate their morphological characteristics and in vitro antioxidant activity. The preparation process was optimized through single-factor and orthogonal experiments, with reaction temperature, time, and polysaccharide concentration as variables, using the A₄₁₀/A₄₉₀ ratio as the evaluation index. The synthesized APPCS-SeNPs were characterized by scanning electron microscopy, transmission electron microscopy, dynamic light scattering, X-ray diffraction, and X-ray photoelectron spectroscopy for morphology, particle size, zeta potential, and structure. Antioxidant activity was assessed by measuring total antioxidant capacity, reducing power, and DPPH radical scavenging rate. The optimal preparation conditions were determined as 70 ℃, 1 h, and a polysaccharide concentration of 4 mg/mL, yielding an A₄₁₀/A₄₉₀ ratio of 2.0403±0.0037. The APPCS-SeNPs were spherical and uniformly dispersed, with an average particle size of 178.47±4.07 nm, a zeta potential of -22.2±0.99 mV, and a selenium content of 16.21%, existing in a zero-valent (Se⁰) amorphous form. The nanoparticles demonstrated good stability for 30 days under light-protected storage at 4℃. Compared to APPCS alone, APPCS-SeNPs exhibited superior total antioxidant capacity, reducing power, and DPPH radical scavenging ability. At a concentration of 0.8 mg/mL, the antioxidant activity was enhanced by 24.62%, 17.36%, and 8.44%, respectively, indicating a more potent antioxidant effect. In conclusion, APPCS-SeNPs possess favorable stability and significant antioxidant capacity, providing a theoretical foundation for the high-value utilization of saffron resources and the application of selenium nanoparticles in functional foods.