Abstract: Sheeting has been widely used to form the gluten network structure for the high product quality of the wheat-based food products. This study aimed to systematically investigate the effects of sheeting parameters on the molecular structural characteristics, rheological properties, moisture distribution, and gelatinization properties of high-fiber dough and the specific volume, height-diameter ratio, hardness, and microstructure of high-fiber steamed buns. The key sheeting parameters were selected as the different sheeting cycles (0, 5, 10, 15, 20, and 25 passes with a gradient of 5 passes) and three folding-feeding modes, including Two-fold Folding with 90° Spinning and Backward feeding (TWFSB), Trisection Folding with 90° Spinning and Backward feeding (THFSB), and Four-fold Folding with 90° Spinning and Backward feeding (FOFSB). A series of advanced analytical techniques was employed, including Fourier transform infrared spectroscopy, X-ray diffraction, rapid viscosity analysis, texture profile analysis, dynamic rheology measurement, low-field nuclear magnetic resonance (LF-NMR) with magnetic resonance imaging (MRI), and scanning electron microscopy (SEM), to characterize and evaluate the samples. The results showed that moderate sheeting effectively optimized the performance of high-fiber dough. There were the uniform distribution of moisture, extensibility, anti-gelatinization, the ordered protein secondary structures, and starch crystallinity of high-fiber dough. The optimal THFSB was achieved in the 15 sheeting cycles among all samples. Correspondingly, the high-fiber steamed buns exhibited the best quality with a specific volume of 2.75 mL/g, a height-diameter ratio of 0.72, and a hardness reduced to 850 g. Meanwhile, the high-fiber dough formed a dense and stable gluten network, with a more uniform moisture distribution and high rheological properties. In contrast, excessive sheeting led to adverse effects: ordered protein structures were degraded into random coils and β-turns, damage to starch granule structures and gluten network continuity, the extensibility, and gas-holding capacity of high-fiber dough. Ultimately, the significant deterioration also caused the quality of high-fiber steamed buns, such as the reduced specific volume, height-diameter ratio, high hardness, and uneven microstructure. Three folding-feeding modes showed that: The TWFSB offered the higher processing efficiency, due to the fewer folding layers but insufficient stability in structure and quality; The THFSB with moderate folding layers shared the uniform distribution of mechanical forces during sheeting, suitable for the full extension and cross-linking of gluten proteins, thus indicating the best stability in both high-fiber dough properties and high-fiber steamed buns quality; The FOFSB with excessive folding layers led to uneven mechanical force distribution and easy lateral dislocation between layers, resulting in limited effect on the formation and reinforcement of the gluten protein network and structural stability. Appropriate sheeting cycles and folding-feeding modes were the key technical factors to enhance the quality of high-fiber steamed buns. Especially, excessive sheeting was avoided during industrial production. There was the regulatory mechanism of sheeting on the physicochemical and structural properties of high-fiber dough and the quality of high-fiber steamed buns. The finding can provide practical guidance for the industrial production of high-quality high-fiber steamed buns in food processing.