To explore the chemical composition and skincare activities of different tissue parts of Arundina graminifolia, this study selected the "Yue Mo No.1" Arundina graminifolia as material. Ultrasonic-assisted extraction with 80% ethanol was performed on its tissues (root, stem, leaf, flower, fruit, protocorm) and the whole plant. The contents of total flavonoids, total polyphenols, and total stilbenes in extracts from different tissues were determined. Skincare activities were evaluated based on DPPH and ABTS radical scavenging capacities, tyrosinase inhibitory activity, antibacterial effects against three acne-causing bacteria (Staphylococcus aureus, Staphylococcus epidermidis, and Cutibacterium acnes), and sunscreen performance. Results showed that root extracts exhibited significantly higher levels of total flavonoids, polyphenols, and stilbenes than other tissues. In antioxidant assays, root extracts demonstrated optimal DPPH and ABTS radical scavenging activities, achieving 90.88% at 0.5 mg/mL and 91.78% at 0.25 mg/mL,respectively. Tyrosinase inhibition tests revealed a remarkable inhibition rate of 97.06% for root extracts at 4 mg/mL, significantly surpassing the positive control (arbutin). Antimicrobial experiments indicated that root extracts exhibited the strongest antibacterial effects against acne-causing pathogens, with the lowest MIC and MBC values (2 mg/mL and 4 mg/mL, respectively) against S. aureus, demonstrating potent bactericidal efficacy. Sunscreen evaluation showed that root extracts achieved an SPF value of 21.51 in the UVB range and exhibited broad-spectrum UVA absorption with stable average UV absorption rates. Comprehensive skincare activity assessments revealed Arundina graminifolia"s potential for antioxidant, whitening, anti-acne, and UV-protective applications. This study provides a theoretical foundation for further development and utilization of Arundina graminifolia in food, cosmetics, and pharmaceutical industries.