Abstract: Off-grid wind–solar hydrogen production provides an effective route for converting fluctuating renewable electricity into green hydrogen, yet the random output of wind and solar power brings three key problems to alkaline electrolyzer arrays: low-load efficiency decline, elevated overlimit risk of hydrogen-to-oxygen (HTO), and uneven service-life degradation among units. To address these issues and improve system comprehensive performance, this paper proposes a dual-layer operation strategy for off-grid wind-solar hydrogen production systems balancing efficiency, safety constraints and service-life equalization. First, electrolyzer efficiency, multi-state operation, HTO safety and life degradation models are established. The efficiency model describes the nonlinear relationship between input power and hydrogen production efficiency, while the HTO model determines the minimum safe operating power under the HTO concentration limit. The life degradation model quantifies degradation effects of load variation and start-stop processes, revealing the coupling mechanism among power allocation, safety constraints and electrolyzer aging. On this basis, the optimal efficiency power and minimum safe operating power are determined as core control thresholds. The upper layer performs real-time power allocation and unit scheduling. According to available wind-solar input power, combined with the optimal efficiency point, minimum safe operating power and single-unit rated power, it dynamically determines the number of operating units and per-unit assigned power. When renewable power is insufficient, it avoids simple average allocation and keeps fewer electrolyzers in high-efficiency safe regions; when power is sufficient, it distributes load across multiple units to boost utilization and prevent overload, ensuring the array runs in an efficient and safe interval. The lower layer implements life-equalizing rotation on a longer time scale. It selects the operating unit with the largest cumulative degradation as the switch-out candidate, and the standby unit with the smallest cumulative degradation as the switch-in candidate. Rotation is executed only when life equalization benefit exceeds start-stop degradation costs, suppressing invalid start-stops while achieving balanced degradation across units. A case study with annual typical wind-solar scenarios compares three strategies: sequential start-stop, fixed-period rotation, and the proposed strategy. Results show the strategy can control HTO content within 2%. Taking weak summer operating conditions as an example, compared with the two benchmark strategies, hydrogen production efficiency increases by about 1.1% and 8.7%, and hydrogen yield rises by about 2.8% and 15.8% respectively. Annual total life degradation is also lower than both reference strategies. The results verify that the proposed dual-layer strategy coordinates efficiency, HTO safety and life equalization, providing a practical operation method for reliable off-grid wind-solar hydrogen production.