Abstract: To address the textural defects of high hardness and easy retrogradation in gluten-free steamed bread, and promote its industrial production and market development, this study investigated the effects of glucan molecular weights (Mw: 1×10⁴, 5×10⁵, 2×10⁶ g/mol) and addition levels (0.5%, 1%, 2%) on the quality and starch retrogradation behavior of buckwheat gluten-free steamed bread. The results showed that the addition of glucan increased the gelatinization enthalpy of starch and increased the proportion of strongly bound water (A₂₁) from 23.81% to 28.43%. Meanwhile, the elastic modulus (G') and viscous modulus (G'') of the dough were significantly improved. The 2% T2000 (glucan with Mw of 2×10⁶ g/mol) treatment group exhibited the optimal anti-staling effect (P<0.05). This treatment reduced the initial hardness of steamed bread by 34.60%, increased the porosity by 87.12%, decreased the hardness increase rate by 11.39% compared with the control group during a 3-day storage period, and lowered the starch retrogradation enthalpy (ΔH) by 88.68% relative to the control group. The underlying mechanism might be that glucan compacted and stabilized the protein network of the dough, increased the area proportion of the protein network in the dough, and inhibited starch swelling. As a result, more intact starch granules were well embedded in the protein network. In conclusion, glucan can inhibit starch retrogradation and water migration in steamed bread by encapsulating starch granules. Among all treatments, the synergistic effect of glucan T2000 (Mw=2×10⁶ g/mol) and a 2% addition level achieves the maximum retardation of starch retrogradation and reduction of steamed bread hardness.