Background Mild traumatic brain injury (mTBI) affects approximately 42 million individuals annually, constituting a major global public health challenge. The 11.7T ultrahigh-field magnetic resonance imaging (MRI) offers novel strategies for tracking microstructural dynamics and elucidating repair mechanisms in mTBI.Objective To investigate the effects of ultrashort wave (USW) intervention on dynamic gray matter volume (GMV) changes and neurobehavioral functions in mTBI rats using 11.7T MRI.Methods Forty-five male Sprague-Dawley rats were randomly divided into mTBI group (single blast waveinduced mTBI model), USW group (mTBI with USW intervention), and control (Ctrl) group (no injury or intervention), with 15 rats in each group. Longitudinal 11.7T MRI T2-weighted imaging was performed during acute (3-5 days), subacute (2 weeks), and chronic (1 month) phases. Voxel-based morphometry (VBM) was applied to analyze whole-brain GMV alterations, while open field test (OFT) and elevated plus maze (EPM) were synchronously conducted to quantify locomotor activity and anxiety-like behaviors. Results Compared to the Ctrl group, the mTBI group exhibited significantly reduced GMV in 11, 5, and 4 clusters at 3-5 days, 2 weeks, and 1 month, respectively (P＜0.05), predominantly involving the prelimbic system, striatum, and parietal associative cortex. USW intervention markedly attenuated GMV atrophy, with 4/6, 3/4, and 2/3 clusters showing GMV recovery at the corresponding time points (P＜0.05). Longitudinal analysis revealed gradual GMV recovery in the mTBI group over 1 month, whereas the USW group achieved stable GMV levels by 2 weeks. The mTBI group displayed acute locomotor deficits (increased % slow movement time vs Ctrl, P＜0.01) and persistent anxiety-like behaviors (reduced open-arm activity vs Ctrl, P＜0.05). In contrast, the USW group showed significant improvements in locomotor function and anxiety-like responses by 2 weeks (increased total distance and open-arm activity, P＜0.05), with anxiety indices normalizing to Ctrl levels at 1 month (P＞0.05), while the mTBI group retained chronic anxiety (reduced open-arm entries, P＜0.05). Correlation analysis identified significant associations between GMV reductions in the right prelimbic system (r=-0.631) and striatum (r=-0.645) with increased % slow-motion time, and between left parietal associative cortex GMV loss (r=0.727) and reduced open-arm time (P＜0.05).Conclusion VBM analysis based on 11.7T MRI sensitively captures dynamic GMV evolution post-mTBI. USW intervention promotes GMV restoration, mitigates acute motor deficits, and alleviates chronic anxiety-like behaviors, thus providing dual imaging and behavioral evidence to support precision rehabilitation strategies for mTBI.