Cross-modal hashing has garnered considerable research interest due to its rapid retrieval and low storage costs. However, the majority of existing methods suffer from the limitations of context loss and information redundancy, particularly in simulated textual environments enriched with manually annotated tags or virtual descriptions. To mitigate these issues, we propose a novel Visual-Textual Prompt Hashing (VTPH) that aims to bridge the gap between simulated textual and visual modalities within a unified prompt optimization paradigm for cross-modal retrieval. By seamlessly integrating robust reasoning capabilities inherent in large-scale models, we design the visual and textual alignment prompt mechanisms to collaboratively enhance the contextual awareness and semantic capabilities embedded within simulated textual features. Furthermore, an affinity-adaptive contrastive learning strategy is dedicated to dynamically recalibrating the semantic interaction between visual and textual modalities by modeling the nuanced heterogeneity and semantic gaps between simulated and real-world textual environments. To the best of our knowledge, this is the first attempt to integrate both visual and textual prompt learning into cross-modal hashing, facilitating the efficacy of semantic coherence between diverse modalities. Extensive experiments on multiple benchmark datasets consistently demonstrate the superiority and robustness of our VTPH method over state-of-the-art competitors.