Abstract: Objective: This study aimed to design and fabricate a probiotic Weizmannia coagulans BC99 (W. coagulans BC99) emergency energy bar with high nutrition, high energy, and anti-fatigue properties. Methods: Taking sensory evaluation as the response value, the formulation of energy bar sandwich was optimized by a Box-Behnken design experiment. The contents of protein, fat, carbohydrate, moisture, ash, dietary fiber, and the composition of amino acid and fatty acid were analyzed. Subsequently, a fatigue mice model was established through three weeks of swimming training to evaluate the anti-fatigue function of the probiotic energy bar. The corresponding exhaustion time, glycogen content, and contents of fatigue factors, inflammatory cytokines, and oxidative stress factors in serum were measured. Results: The optimal conditions of the probiotic energy bar sandwich were as follows: 35 g of nuts, 45 g of oats, 15 g of chia seeds, syrup composite ratio (W_maltose:W_{white granulated sugar}) of 2.0, and stirring time of 9.0 minutes. Under these conditions, the sensory evaluation of the energy bar sandwich containing W. coagulans BC99 probiotics was 93 score. The coating of the energy bar contained a count of W. coagulans BC99 of 1.43×10⁸ CFU/g, and the nutritional analysis showed abundant essential amino acids and unsaturated fatty acids. The intervention with the W. coagulans BC99 energy bar resulted in significantly increased levels of liver glycogen and muscle glycogen (P<0.05), significantly enhanced glucose metabolism key enzyme hexokinase (P<0.05), significant reduction in fatigue factors lactate and urea nitrogen in serum (P<0.05), regulated levels of inflammatory cytokines interleukin-4 and interleukin-1β, significantly increased levels of catalase, superoxide dismutase, and glutathione (P<0.05), and significantly decreased levels of malondialdehyde (P<0.05). Conclusion: The W. coagulans BC99 probiotic emergency energy bar could alleviate fatigue, balanced the levels of inflammatory cytokines, and relieved exercise-induced oxidative stress damage. It is expected to provide technical and theoretical support for the development of probiotic-rich emergency food through this study.