The invention discloses a method for making resin slices of mature grain seeds, which includes the steps of material collection, fixation, rinsing, dehydration, resin penetration, embedding, polymerization, block trimming, semi-thin sectioning and dyeing, and is characterized by: ① using 4% paraformaldehyde‑‑2.5% glutaraldehyde fixative solution for secondary fixation; ②London white glue (LR White) resin with very low viscosity and strong penetrating ability was used as embedding agent; ③Established a Dry cutting technology of mature seeds; ④ Established a 45°C-60°C secondary exhibition method. The present invention overcomes the shortcomings of the mature seed slices produced by conventional methods, such as severe curling, inability to display, easily broken and incapable of iodine staining, and can obtain mature grain seed resin slices with complete and clear tissue and cell structure and obvious contrast. The structure and function of mature seeds provide accurate technical support.