Multimodal fusion is often affected by modality imbalance, which can lead to biased learning and suboptimal fusion.A Shapley-guided alternating training framework has been proposed to prioritize minor modalities adaptively, balancing and enhancing fusion.The method uses Shapley Value-based scheduling to improve training sequences, ensuring under-optimized modalities receive sufficient learning.The proposed approach, evaluated across four benchmark datasets, achieves state-of-the-art results in balance and accuracy in multimodal learning.