Fitness power assist exoskeleton is a lightweight wearable lower limb power support device specially developed for outdoor fitness, long-distance walking training, mountain hiking and endurance exercise load reduction. Built with high-toughness slim composite materials and ergonomic soft wrapping structure, this fitness power assist exoskeleton fits tightly to leg contours without bulky rigid structures, delivering unrestricted natural movement during walking, climbing, stepping and downhill training sessions. Integrated mini real-time gait sensors and adjustable adaptive servo drive system, it intelligently identifies flat fitness trails, uphill slopes and downhill terrain, outputting customizable auxiliary power to hip and knee joints to share body weight and sports backpack loads. It evenly disperses lower limb pressure, alleviates excessive muscle soreness of thighs and calves caused by long-time fitness training, reduces continuous compression wear on knee joints, and stabilizes standard bionic gait to help users extend their exercise duration without premature fatigue. The streamlined compact frame supports quick putting on and foldable storage for easy carrying to gyms, scenic fitness routes and mountain training areas, reaching IP54 dustproof and splash-proof grade to adapt to outdoor sports environments with dust, sweat splashes and light rain. Fully adjustable elastic padded straps fit users of various heights and leg circumferences, avoiding skin friction and tight compression during long training hours. Matched with lightweight detachable lithium batteries, it provides stable continuous power assistance for full-day fitness activities without adding extra weight burden. Bionic flexible joints fully follow human natural bending tracks, paired with simple one-touch power adjustment control that fitness lovers, outdoor trainers and amateur endurance sports enthusiasts can operate effortlessly. Built-in overload protection, balance stabilization and emergency stop safety modules effectively prevent sprains and secondary injuries during strenuous fitness movement. This multi-scenario fitness power assist exoskeleton achieves smooth human-machine motion coordination, greatly improves long-time exercise comfort and extends continuous training endurance while effectively protecting lower limb joints from overloading damage.