Background: This study investigated the effects of combined Rhodiola rosea (RHO) and caffeine (CAF) supplementation on lower limb explosive power and fatigue recovery in volleyball players, aiming to validate their potential synergistic effects. Methods: A randomized, double-blind, placebo-controlled design was implemented involving 48 male volleyball athletes allocated into four groups: placebo (CTR), Rhodiola rosea (RHO), caffeine (CAF), and combined (RHO + CAF). Over four weeks, participants engaged in twice-weekly high-intensity lower limb resistance training, with performance evaluated through multiple tests, including two-step-approach jump height, countermovement jump (CMJ), five-jump test (5 JT), continuous 20 vertical jumps, and intermittent jump recovery alongside Rate of Perceived Exertion (RPE) assessments. Results: Results showed that the combined supplementation (RHO + CAF) group exhibited significant improvement across multiple performance metrics. In particular, the combined group demonstrated the highest increases in jump height and the least power decline during high-frequency jumps, outperforming the CTR and other supplementation groups (p < 0.05). Additionally, RHO + CAF supplementation significantly lowered RPE scores, particularly in the final week of training, indicating improved perceived fatigue and recovery. Conclusions: This study suggests that combining RHO and CAF optimizes high-intensity performance by enhancing explosive power, reducing fatigue, and improving recovery, presenting an effective nutritional strategy for volleyball athletes.