The effects of superfine and conventional grinding on the content, structure, physicochemical properties, and glycemic index of resistant starch in banana flour were compared. The results showed that the resistant starch content of superfine ground banana flour (51.96 g/100 g) was significantly lower than that of flour obtained by conventional grinding (48.76 g/100 g). The non-resistant starch content increased significantly from 20.87 to 21.93 g/100 g. The structure of superfine resistant starch was loose, and its polymerization degree was 56.62%, lower than that of conventionally ground starch (59.48%). However, functional groups were consistent between the two resistant starch samples. Molecular weight distribution of superfine resistant starch was dispersed. The initial temperature of phase transformation T0 (51.8 ℃) was reduced and peak temperature TP (74.4 ℃), final temperature Tc (81.1 ℃), temperature difference ΔT (29.3 ℃), and enthalpy ΔH (1 068 J/g) were elevated. The glycemic index of banana flour produced by superfine grinding (20.92) was significantly higher than that of banana flour produced by conventional grinding (17.12). Superfine grinding decreased resistant starch content, increased non-resistant starch content, loosened particles, decreased crystallinity degree, dispersed molecular weight distribution, reduced initial temperature of phase transition, and increased the temperature range required to complete phase transition. However, it did not affect the functional groups in resistant starch. The glycemic index of banana flour increased, but it remained a raw material with a low glycemic index. In summary, the resistant starch content of banana flour was reduced and the particles of banana resistant starch were degraded; however, superfine grinding increased the heat demand during its phase transition process.