Abstract: The dynamic simulation model for a closed air Brayton cycle system was established to analyze the dynamic response characteristics of the inventory control method under variable load processes with different storage tank volumes. The study comparatively investigated the system dynamic response patterns during load reduction process using bypass control, inventory control, and combined bypass-inventory control strategies. Results show that the storage tank volume constrains the maximum load adjustment depth of inventory control, where larger tank volume enables greater load variation range. Under 75% and 50% load targets, the combined control strategy achieves faster load reduction rate of 18.71% and 16.57% respectively compared to inventory control, while achieving higher cycle efficiency of 20.81% and 37.66% respectively compared to bypass control. Bypass-inventory combined strategy exhibits excellent load tracking capability, effectively enhances both efficiency and flexibility of load reduction regulation and achieves complementary advantages of different control approaches.